As the Distinguished Military Graduate of the Lamar Army ROTC program in 1984, Brian was commissioned as an officer in the U.S. Army and served a 20-year career with numerous training deployments and two operational deployments. In 1990, he deployed to Operation Desert Shield/Desert Storm, where he was awarded the Bronze Star for Exceptional Meritorious Achievement. In 1998, he deployed to Central America as the Joint Operations Officer for Joint Task Force Aguila to execute humanitarian relief operations in the aftermath of Hurricane Mitch. In 2001, Brian was serving on the Department of the Army staff at the Pentagon as the military aide to the Deputy Assistant Chief of Staff for Installation Management.

On September 11, 2001, when American Airlines Flight 77 crashed just yards away from his second floor Pentagon office, Brian was critically wounded and severely burned. Of the burns that covered more than 60 percent of his body, nearly half were third degree in severity. Today, following 39 operations, months of hospitalization and numerous skin grafts, Brian has made a miraculous recovery. Despite physical limitations, he testifies not only to his physical healing, but the ultimate miracle of grace through Christ. He was awarded the Purple Heart for wounds received that day. Upon retirement in July 2004, he was awarded the Legion of Merit.

From 2004 to 2017, Brian and his wife, Mel, operated Face the Fire Ministries, a non-profit organization they jointly founded to support critical-burn survivors and wounded service-members and their families. In 2004, the Birdwells jointly authored Refined by Fire- A Family's Triumph of Love and Faith, which chronicles their life-changing ordeal. Through the years, Brian has been profiled in numerous national and regional media outlets.

Brian was first elected to the Texas State Senate in a June 2010 special election, and has since been re-elected by his constituents five times, averaging more than 85 percent of votes cast. In his seven legislative sessions Brian has consistently received critical acclaim and top ratings from numerous pro-life, pro-business and conservative organizations, including National Federation of Independent Business, Texans for Fiscal Responsibility, Texas Eagle Forum, Texas State Rifle Association/National Rifle Association, Young Conservatives of Texas, Texas Alliance for Life, Texas Right to Life, Americans for Prosperity, Concerned Women for America, Texas Heritage Alliance and Texas Conservative Coalition, among others.

Brian is proud of his diverse and impactful legislative accomplishments, including filing and passing legislation broadening access to higher education, strengthening eminent domain laws protecting landowners, expanding self-defense rights of law-abiding gun owners, strengthening legislative oversight of state river authorities, increasing technical- and associate-degree options for high school graduates and adult students, serving Texas veterans and their family members, and authoring the strongest border security package in Texas history-the Stronger Border, Safer Texas Act. In 2017, Brian led the successful effort to make Texas just the eleventh state in the nation to pass a resolution and corresponding legislation calling for an Article V convention of states. Brian chaired the Sunset Commission for the 2018 interim and 2019 Regular Session, which made numerous improvements to state agencies. One of the most critical reforms which Brian carried was the Texas Alcoholic Beverage Commission bill, which reformed several antiquated provisions of the Alcoholic Beverage Code, among other significant changes as well as other agencies.

Brian serves as Chairman of the Senate Committee on Natural Resources and Economic Development, which provides oversight to the Railroad Commission, the Texas Commission on Environmental Quality (TCEQ), and the Workforce Commission. Senator Birdwell also serves as Chairman of the Senate Committee on Border Security and as a member of the Senate Committees on Business & Commerce, Education, State Affairs, and the Select Committee on Redistricting. Since 2013, Brian has served as Chairman of U.S. Senator Ted Cruz's 22-member U.S. Service Academy Nominations Board.

The Birdwells have been married for more than 30 years and reside in Granbury. They have one son, Matt, a 2013 graduate of Texas Tech University, and a daughter-in-law, Ann Marie, who reside in Tarrant County with the Birdwell's two grandchildren.