Basketball

Prior to entering politics, McMillen was a star basketball player on all levels. In 1970, he was the number one high school basketball player in the U.S. coming out of Mansfield, Pennsylvania, and was the biggest recruiting catch early in Coach Lefty Driesell's career at the University of Maryland, beating out rival Coaches Dean Smith of the University of North Carolina and John Wooden of UCLA for McMillen's services. Wooden instead signed Bill Walton, who proved to be the far more consequential player. McMillen played for the Terrapins from 1971 to 1974,^[4] McMillen was also a member of the 1972 U.S. Olympic Basketball Team that lost a controversial gold medal game to the Soviet Union.

McMillen earned his B.S. from University of Maryland in chemistry, which is part of the University of Maryland College of Computer, Mathematical, and Natural Sciences.^[5] After graduating from Maryland in 1974,^[6] McMillen was drafted with the ninth pick in the first round of the 1974 NBA draft by the Buffalo Braves and the first round of the 1974 ABA Draft by the Virginia Squires.^[7] McMillen signed with the Braves but postponed his entry into the NBA in order to attend the University of Oxford as a Rhodes Scholar. During his time at Oxford, McMillen was a member of the Oxford University basketball team. He also commuted to Bologna, to play for Italian club Virtus Bologna.^[8] During his eleven-year National Basketball Association career, he played for the Braves, New York Knicks, Atlanta Hawks, and Washington Bullets, before he retired in 1986 to pursue his political career.

U.S. House

He was elected to the U.S. Congress as a Democrat to represent Maryland's 4th district, and served 1987–1993 as that district's representative.^[9]

In 1992, the 4th was redrawn as a black-majority district due to a mandate from the Justice Department. His home in Crofton was drawn into the Eastern Shore-based 1st District, represented by one-term Republican Congressman Wayne Gilchrest. Although McMillen did very well in the more urbanized areas of the district near Baltimore and Washington, D.C., it was not enough to overcome Gilchrest's margin on the Eastern Shore, and McMillen lost his reelection bid.

McMillen is thought to be the tallest-ever member of Congress.^[10] At 6 feet 11 inches, he is two feet taller than Maryland Senator Barbara Mikulski, who is believed to be the shortest representative ever.^[11]

Later career

McMillen was appointed to the University System of Maryland's Board of Regents in 2007, where he served until June 30, 2015. He was replaced by Robert R. Neall whom McMillen had defeated for Congress in 1986.^[12] In March 2023, McMillen was again appointed to the Boards of Regents, succeeding Gary L. Attman.^[13]

In September 2015, McMillen was selected to lead the Division I-A Athletic Directors’ Association as it moved from Dallas to Washington, D.C.^[3] He remains President and Chief Executive Officer of the renamed Lead1 Association, now advocating for athletic directors at Football Bowl Subdivision universities.^[14][15]