Thomas Penfield Jackson (1937-2013) was a prominent American jurist who served as a United States District Judge for the District of Columbia from 1982 until his retirement in 2004, continuing in senior status until 2008. Born on January 10, 1937, in Washington, D.C., he graduated from Dartmouth College with an A.B. in 1958 and earned his J.D. from Harvard Law School in 1962. After law school, he clerked for Judge Warren E. Burger of the U.S. Court of Appeals for the District of Columbia Circuit from 1962 to 1963. He served in the U.S. Army from 1959 to 1961 as a military officer before beginning his legal career in private practice at Williams & Connolly in Washington, D.C., where he worked until his judicial appointment in 1982. Jackson presided over several high-profile cases, most notably the landmark Microsoft antitrust litigation in the late 1990s and early 2000s, where he ruled against Microsoft in 2000, finding the company guilty of monopolization and ordering its breakup—a decision later modified on appeal. He was respected for his sharp intellect and no-nonsense courtroom demeanor but faced criticism for his handling of certain cases, including allegations of bias in the Microsoft trial. He passed away on June 15, 2013, in Washington, D.C., at the age of 76.