He is a partner in the Washington, D.C. office of McGuireWoods LLP where he is head of the firm's Crisis Response practice and co-head of its white collar team.

His father, George J. Terwilliger, Jr., was a civil engineer and Navy veteran with combat experience in the Pacific in World War II.

"[6] Terwilliger commented on the Iran–Contra affair in a February 6, 2001 appearance on a CNN titled "Burden of Proof: Ronald Reagan's Legal Legacy".

[7] During the Florida 2000 election recount, Terwilliger was co-leader of Republican President-elect George W. Bush's legal team[8] and was "an advisor to the Bush-Cheney Transition and counselor to designated cabinet and other prospective appointees.

"[2] In June 2001, Bush administration spokesman Ari Fleischer was asked in a White House press briefing whether Terwilliger was a leading candidate to head the Federal Bureau of Investigation.

[11][12] In April 2007 Terwilliger served as a panelist for the Brookings Institution Judicial Issues Forum entitled "Politics and the Justice Department: Finding a Path to Accountability".

"Investigators are look[ing] into allegations that Gonzales lied to lawmakers and illegally allowed politics to influence hiring and firing at the department.