He is best known for portraying Brad Majors in The Rocky Horror Picture Show (1975) and Mayor Randall Winston in the sitcom Spin City (1996–2002).

[1] He is the son of Elizabeth "Betty" (née Defendorf), a housewife, and Henry "Bud" Bostwick, a city planner and actor.

[3] Bostwick attended San Diego's United States International University in 1967, majoring in acting, got his start on the Hillbarn Theatre stage now located in Foster City, and worked for a time as a circus performer.

[5][6] Their sole album, released in 1970, was produced by Jeff Barry, and generated a minor Billboard hit single, "Lady Love.

In 1972, Bostwick originated the role of bad boy Danny Zuko in the stage production of Grease, earning a Tony Award nomination for his performance.

In 1981, Bostwick starred in the TV series adaptation of the 1978 film Foul Play, with his role modeled after Chevy Chase's and co-star Deborah Raffin in Goldie Hawn's part.

[10] In June 2009, he played Father Jimmy, the ineffective exorcist in the independent horror comedy The Selling, written by Gabriel Diani and directed by Emily Lou.

Other television credits include guest appearances in Charlie's Angels, Hawaii Five-O, The Golden Palace, Grace Under Fire, and Las Vegas.

Bostwick was supposed to appear on the third season of Private Practice as "the Captain," a father of the Addison Montgomery character, but had to resign due to a scheduling conflict.

In 2015, he portrayed Collin Winthrop, father of the Gig Harbor Killer, in the season-ending CSI: Crime Scene Investigation episode "The End Game.