Tim Matheson is an American actor and director. Some of his best-known acting roles include the title character of the 1960s animated Jonny Quest TV series, Eric "Otter" Stratton in the 1978 comedy film National Lampoon's Animal House, and the recurring role of Vice President John Hoynes in the 2000s NBC drama The West Wing, which earned him two Primetime Emmy Award nominations for Outstanding Guest Actor in a Drama Series.

Matheson was born in Glendale, California, the son of Clifford Matthieson, a training pilot, and Sally Matthieson. Matheson served a tour of duty in the United States Marine Corps Reserve. 

At age 13, Matheson appeared as Roddy Miller in Robert Young's CBS nostalgia comedy series Window on Main Street during the 1961–1962 television season. In the 1962–1963 season he appeared in two episodes of Leave It to Beaver, cast as Mike Harmon, a friend of Beaver’s. In 1964, he provided the voice of the lead character in the animated series Jonny Quest. He also supplied the voices of Sinbad Jr. the Sailor in the 1960s Hanna-Barbera animated series Sinbad Jr. and his Magic Belt and Jace in Space Ghost. He co-starred as Joe Hardy, opposite Richard Gates as Frank Hardy, in a 1967 pilot episode for what would have been a TV series called The Hardy Boys, based on the novel series of the same name, but the series was not picked up. He played the role of the oldest son, Mike Beardsley, in the film Yours, Mine and Ours (1968), which starred Lucille Ball and Henry Fonda.

In 1969, Matheson joined the cast of NBC's television Western The Virginian in the eighth season as Jim Horn. He had a guest role in the 14th episode of the second season of Night Gallery, in the story "Logoda's Heads". In the final season of the television Western Bonanza in 1972–1973, Matheson played Griff King, a parolee who tries to reform his life as a worker at the Ponderosa Ranch under Ben Cartwright's tutelage. He portrayed a corrupt motorcycle cop, Phil Sweet, who was part of a death squad with some other young cops in the film Magnum Force (1973). Matheson also appeared earlier in the CBS situation comedy My Three Sons. In 1975, he guest starred in CBS's short-lived family drama Three for the Road.