Alan Douglas Ruck (born July 1, 1956) is an American actor. He played Cameron Frye, Ferris Bueller's hypochondriac best friend in John Hughes's Ferris Bueller's Day Off (1986), and Stuart Bondek, a lecherous, power-hungry member of the mayor's staff in the ABC sitcom Spin City. His other notable films include Bad Boys (1983), Three Fugitives (1989), Young Guns II (1990), Speed (1994), Twister (1996), and Kickin' It Old Skool (2007). In 2016 he co-starred with Geena Davis in an updated Fox TV adaptation of William Peter Blatty's best-selling novel The Exorcist. He also plays the role of the oldest son, Connor Roy, in the HBO series Succession.