Matthew Garcia joined Cornerstone in December of 2024, expanding the firm's Texas footprint to Dallas. A seasoned government and public affairs executive with over two decades experience in the Dallas Region, Matt brings a wealth of experience in policy, advocacy and stakeholder engagement. He joins Cornerstone from the Dallas Regional Chamber, where he served as Senior Vice President of Public Policy and Advocacy. In this role, he spearheaded the organization's public policy strategy, while remaining closely engaged with legislators, key stakeholders and C-level executives across the Dallas Region for one of the largest Chambers of Commerce in Texas.

Prior to his time at Dallas Regional Chamber, Matt worked as the Director of External Affairs for Leon Capital Group where he developed the firm's public affairs strategies across their multiple business lines.

Previously, Matt served in the United States House of Representatives, first as District Director (2010-2013) and then as Chief of Staff-Texas (2013-2018), managing Rep. Pete Sessions' (R-TX) office and serving as a key advisor on energy, transportation and general business issues for Texas. Notably, Matt served as the North Texas congressional point of contact working with area city officials, the North Texas Municipal Water District (NTMWD) and the Army Corps of Engineers to bring online Bois d'Arc Lake, the newest major reservoir in Texas in over 30 years. Matt also worked alongside emergency response teams at the city, county and state levels during the 2014 Ebola crisis in Dallas to deliver accurate and timely public communication while leading information coordination with federal agencies, including the National Institute of Health and the Department of Health and Human Services.

He earned his bachelor's degree in finance from the McCombs School of Business at the University of Texas at Austin. Garcia currently serves as Director of the Texas Association of Business, The Dallas Zoo and the Texas Lyceum, and member of the following organizations: McCombs School of Business BBA Advisory Board, Simmons Cancer Center Community Advisory Board, Reading Partners North Texas, the State Fair of Texas Chairman's Task Force, the YMCA of Metropolitan Dallas Brand Advancement Committee and the SMU Corporate Communications and Public Affairs Advisory Board.

6-10 years

A native of Michigan's rugged, beautiful Upper Peninsula, Matt joined Karoub Associates in 2011 after serving eight years on legislative staff for a former State Senator and Senate Minority Leader. He holds degrees from Western Michigan University, Gogebic Community College, and is a 2005 Fellow of the Michigan Political Leadership Program (MPLP) at Michigan State University.

An avid golfer, musician, and NASCAR enthusiast, Matt and his wife Rebecca reside with their son in Okemos.

20+ years

I served over twenty years at the local, state legislative and executive levels of government before entering the private sector. My background includes serving former Massachusetts Governor Mitt Romney as Legislative Director and working along-side the former Speaker of the Massachusetts House of Representatives, Thomas M. Finneran. I also worked as the Director of Government Relations & Educator Licensure for the Massachusetts Department of Education. Elected to two terms as a Revere, Massachusetts City Councilor-At-Large, and a member of Revere's School Committee for 6 consecutive years, I am also a licensed Superintendent, Assistant Superintendent and School Business Administrator in Massachusetts.

Throughout my career, I have been fortunate to establish lasting relationships which have led to noteworthy victories on behalf of clients. Whether it is legislative or regulatory; fiscal or procurement related, my respect, access and ability to nimbly navigate government is unrivaled.

Tony Essalih joined Cornerstone in 2011 as a co-lead of the firm's flagship Texas office in Houston. He spent 12 years on Capitol Hill and came to Cornerstone from the office of Congressman John Culberson (R-Houston). Tony worked for Congressman Culberson for 10 years, the last five as his chief of staff. Prior to becoming chief of staff, Tony served in a variety of capacities including legislative assistant, legislative director, communications director, and deputy chief of staff. He spent eight years in Washington, D.C. before relocating to Houston in 2007.

As chief of staff, Tony was responsible for guiding the day-to-day operations of the Congressman's Washington and Houston offices, and oversaw a 15-member staff under a fixed budget. Outside of the office, he served as the principal liaison to the Congressman's campaign committee and provided strategic counsel and advice related to his re-election efforts. Tony's areas of policy expertise include transportation, energy, budget and appropriations. Tony also led outreach efforts and served as an emissary on behalf of the Congressman with state lawmakers in Austin and local elected officials in Houston.

Prior to Culberson's election in 2001, Tony worked as a legislative assistant for Congressman Culberson's predecessor, former House Ways and Means Committee Chairman Bill Archer. Tony's began his tenure on Capitol Hill with former House Natural Resources Committee Chairman Doc Hastings.

Tony has advised and assisted numerous local, state, and federal campaigns. He serves on the board of the National InterFaith Foundation, the Advisory Board for the Houston Technology Center, spent two years on the Board of the Spring Branch Medical Center and was a member of Houston Mayor Annise Parker's transition team in 2010.

Tony was born and raised in Fredericksburg, VA and received his B.A. in Political Science from Mary Washington College. He was a member of Mary Washington's NCAA semifinalist men's soccer team. He lives in Houston and has two angelic daughters, Grace and Libby.

Zoe Halfmann joined Cornerstone as a Principal in our Dallas office in September 2025.

Prior to Cornerstone, she was Chief of Staff to Dallas City Councilmember Paula Blackmon. In this role, she advised on key policy initiatives related to preemption, mental health, , fentanyl and funding for district projects. She oversaw the Councilmember's agenda, collaborated directly with city executive staff and fellow councilmembers, managed internal operations and coordinated media and communications strategy.

Prior to that, Zoe served as Vice President of Public Policy at the Dallas Regional Chamber, where she managed local government relations and led the organization's work in critical areas including infrastructure, healthcare and water policy. She also helped lead the formation of the Good for Texans PAC, provided on the ground support during the 88th Session of the Texas Legislature, and revitalized the organization's Infrastructure Task Force to advance regional priorities. Zoe also organized high-profile events including coordinating state and federal fly-ins, hosting the Texas Governor and the Speaker of the House, and planning roundtables with local and national stakeholders.

In addition, Zoe has held various roles within the City of Dallas including Legislative Manager, Council Liaison and Policy Advisor and Legislative Coordinator.

She holds a Master's in Public Administration from the University of North Texas, where she was a Hatton Sumners Scholar. She also has a Bachelor of Arts in Political Science from the University of Arkansas.

Ross Giesinger brings over a decade of legislative experience at the Texas Capitol to the Cornerstone team, having served for six legislative sessions in both the Texas House and Senate.

Most recently, Ross worked as a policy advisor to Dade Phelan, Speaker of the Texas House, of Representatives, during the 87th Regular Session, where he assisted with the passage of over 80 pieces of legislation. Additionally, Ross drafted and managed several bills filed in response to Winter Storm Uri, including SB 3, one of the most comprehensive energy reforms in Texas in the last 20 years.

Prior to his time in the House, Ross spent several years working as general counsel and legislative director for Sen. Lois Kolkhorst (R-TX) and as the director of the Senate Committee on Health and Human Services. While at the Senate, Ross assisted with the passage of nearly 300 bills and worked to obtain funds for a variety of initiatives, including legislation that secured permanent funding for Texas State Parks.

Ross began his career at the legislature in 2010 as a drafting attorney for the Texas Legislative Council. During his time with the state, he has drafted thousands of pieces of legislation, allowing him to develop expertise in a wide variety of subject areas, including energy, healthcare, water, land use and development, transportation, insurance, labor, agriculture, wildlife, taxation, and state budgeting.

Ross is a graduate of the University of Texas at Austin and Southern Methodist University's Dedman School of Law. He is a member of the Austin Young Lawyers Association and was recently elected to serve on the Council of the Texas State Bar's Legislative and Campaign Law Section. Ross also serves as a Steward of the Wild for the Texas Parks and Wildlife Department and has been active in the Austin Ballet Guild, the Trail Foundation, and CCA. He and his wife Courtney live in Austin with their young son Henry.

6-10 years

Julies Family Learning Program Board Member
Norwell Board of Selectman
2019- Medicine Wheels King of the Hill, presented to man of the year
Major General Henry Knox Unsung Hero
Registry of Deeds "Good Deed Award"
South Boston World War II Memorial Committee
Sons and Daughters of South Boston

Over the course of his career Rull has built a vast network of Government, Political, Non Profit and Business Officials. Rull has been fixture at Boston City Hall the past 20 years.

Joe Rull is a seasoned government, political, real estate development, procurement and operations advisor. Rull began his career in government over two decades ago when Boston Mayor Tom Menino appointed him as neighborhood liaison for the Office of Neighborhood Services and rose to become a special assistant to the Mayor. He also worked for several state agencies, primarily in capacities related to development and real estate, most notably Massachusetts Port Authority (Massport) and Division of Capital Asset Management and Maintenance (DCAMM). Rull returned to Boston City Hall as Chief of Operations for Mayor Marty Walsh overseeing The Office of Intergovernmental Affairs, The Office of Civic Engagement, Property and Construction Management, Labor Relations, Human Resources and Health Benefits, Retirement Office.

Rull has extensive political campaign experience, advising the campaigns of both Mayors Thomas Menino and Martin Walsh, Governor Deval Patrick, Senators Elizabeth Warren and Ed Markey, and Congressman Stephen Lynch to name a few.

Rull founded MJR consulting in 2015 specializing in Government Relations, Real Estate Development, Licensing, Permitting and Political Strategy.

6-10 years

Dianne began her career at the Massachusetts State House alongside freshman State Representative Marty Walsh, now former Secretary of the US Department of Labor. From there, she led public policy and intergovernmental relations for Massachusetts public safety and public health agencies. In those roles, she secured major funding for operations and capital improvements, and policies to improve services to the Commonwealth's most vulnerable residents. Shortly after Walsh became Mayor in 2014, she helped him build out Boston's first-ever Economic Development cabinet.Her experience includes public policy, legislative, and regulatory work for legislative, executive, and independent state agencies, municipal government, political campaigns, and private consulting. Dianne specializes in public safety, construction trades issues, the cannabis industry, and public health.

Part of Boston's State and Local Affairs practice, representing clients ranging from Fortune 50 companies to non-profits. Represents a diverse set of clients; i.e., energy, high tech, healthcare, finance, consumer, and non-profit. Mulvey manages Boston's state and municipal procurement practice.

Prior to coming to DSG, Mulvey was a Principal at Fort Hill Advisors, a boutique lobbying firm located on Beacon Hill in Boston. Mulvey also worked in the Government Law & Strategies Legal practice at the Law Firm of Brown Rudnick. He also served as General Counsel for the Retailers Association of Massachusetts.

Mulvey was born and raised in Belmont, MA. He currently resides in Reading, MA with his wife and four sons. Mulvey is a 1991 graduate of Stonehill College and a 1997 graduate of the Massachusetts School of Law.

Laura Alexander joined Cornerstone in October of 2025 as a Principal for our Texas office, and is based in Houston. She supports client teams in a variety of issue areas.

Prior to Cornerstone, Laura served as Vice President of Public Policy at the Greater Houston Partnership. In this role, she led advocacy on water infrastructure, workforce development and public school funding; managed member fly-ins and delivered key outcomes during the 89th Texas Legislative Session, including local appropriations for the City of Houston, extension of research & development franchise tax credits and a constitutional dedication of funds for water projects.

Laura previously practiced public finance law, holding roles with a number of firms in Louisiana focusing on environment, energy, tourism, housing and elections. She also served as Executive Director of the Louisiana Institute for Children in Families, where she advanced foster care and adoption reforms and launched the Louisiana Foster Youth Intern Program to prepare former foster youth to testify before the Legislature.

Laura holds a Juris Doctor from Loyola University New Orleans College of Law and a BA in Mass Communication from Louisiana State University.

Max Moll joined the Cornerstone Public Affairs team April of 2023, bringing a public affairs and strategic communications presence to Cornerstone's Texas offices. In his previous role as chief engagement officer at the Houston Independent School District, he oversaw government relations, communications, family and community engagement and board relations for the nation's eighth largest school district. He also oversaw the district's legislative affairs work and external lobby team, ensuring alignment and execution of district's legislative priorities. In addition, he represented the district with external stakeholders, in traditional and digital media appearances, and on panels and other various speaking opportunities. He was also the lead spokesperson for the district and main point of contact for elected officials, advocacy groups and private industry.

Prior to working at HISD, Max served as the chief communications officer & deputy director for the Office of the Houston City Controller, Chris B. Brown. He spearheaded all communications initiatives for the Office of the City Controller, working across the City of Houston's 22 departments to help unify external and internal communications. Max served as liaison between Controller's Office and the city's investors, developing key external messaging relating to investment strategy, portfolio performance, and maintaining key relationships with city's investor base. In addition, and in partnership with the Controller's Office Treasury Division, Max helped oversee the city's Environmental, Social, and Governance (ESG) investments, helping grow the portfolio to over $950 million.

Max also served as the chief of staff to the CEO of the Houston Hispanic Chamber of Commerce, where he oversaw the development and execution of the Chamber's public affairs and community outreach efforts, legislative advocacy campaigns and external affairs projects. Also, he served as the main point of contact for media, securing comprehensive coverage and managing all media relationships on behalf of the Chamber and its members.

He holds a master's in business administration from Boston University, master's in political management from George Washington University, and a bachelor's in mass communication from LSU.

Martin Hubert brings a wealth of state government experience to the clients of Cornerstone Government Affairs. From his early career as chief counsel to the Senate Natural Resources Committee to his gubernatorial appointment as a commissioner of the Texas Commission on Environmental Quality to his eight years as the deputy comptroller of Texas, Hubert has managed thousands of employees and millions of taxpayer dollars under both Democrat and Republican administrations.

Martin was the 2008 recipient of TSABAA's Administrator of the Year Award. Presented annually, this prestigious award was established to formally recognize state employees who have demonstrated outstanding leadership skills and who have made significant contributions to state agency business administration.

As the final general counsel to legendary Lt. Governor Bob Bullock, Martin learned the mastery of government relations from some of the most influential leaders in Texas history. His knowledge of agriculture stems from generations of the Hubert family's cow/calf and farming operations in South Texas and serving as the Texas Deputy Commissioner of Agriculture for eight years. Martin offers a unique combination of legal, natural resources, tax policy and state government procedural expertise.

Hubert is a graduate of the Georgetown University Law Center and St. Mary's School of Law. He was Brigade Executive Officer in the Corps of Cadets at Texas A&M University, where he was a member of the Ross Volunteers Honor Guard and the Singing Cadets. He successfully completed Army Ranger School and served in the U.S. Army Reserves. He is a marathon runner and coaches his son's little league teams.

Hubert is a second tenor and helps raise money for Legal Aid through the Travis County Bar Association's "Bar and Grill" fundraisers. He and his wife Celeste live in a historic home in Austin, where they are involved with the Austin Symphony, St. Theresa's Catholic Church and School, and the happily busy lives of their children Belle and Patrick.