Von Dohlen was born in Augusta, Georgia, and raised in Goliad, a small town in south Texas. He has German ancestry from his paternal side. As a child he wished to become a jockey, but grew too tall for his dream. He studied Theater at University of Texas, and graduated from Loretto Heights College in Denver, Colorado. From there he moved to New York City to pursue a career on the stage.
Lenny Von Dohlen’s film debut was in Academy Award-winning Tender Mercies, starring Robert Duvall, written by Horton Foote and directed by Bruce Beresford in 1983. In 1984, Von Dohlen played the lead role in the cult film MGM/UA’s Electric Dreams. Other roles include: Under the Biltmore Clock (1985); Dracula's Widow (1987); Blind Vision (1992); Twin Peaks: Fire Walk with Me (1992); Jennifer 8 (1992); Ed Zwick’s Leaving Normal (1992) and the title role in Billy Galvin (1986) opposite Karl Malden.
He played one of the villains in Twentieth Century Fox’s Home Alone 3 (1997). He has appeared in acclaimed independent films such as Tollbooth (1994), Bird of Prey (1996), One Good Turn (1996), Entertaining Angels (1996), Cadillac (1997) and Frontline (1997). In 2007, he appeared in Beautiful Loser, playing the role of Reggie as an adult, and in Teeth, a Sundance and Berlin Film Festival Dramatic Competition nominee. In 2010, he played Elder Daniel in Downstream and in the same year he played Sheriff Jack Carter in a short film called Night Blind (2010). In 2012/13, he was seen in Camilla Dickinson and White Camellias. In 2015, Lenny Von Dohlen played the title role of legendary film director Oskar Knight in Near Myth: The Oskar Knight Story.
Von Dohlen's first television role was in NBC's Emmy-award winning Kent State (1981). Others include Don't Touch, directed by Beau Bridges; The Equalizer; Tales From the Darkside; Miami Vice; thirtysomething (1987); The Lazarus Man (playing John Wilkes Booth), Picket Fences (playing the gay brother of Marlee Matlin's character (1992)); as the diabolical Mr. Cox in a recurring role on The Pretender (1999); Chicago Hope (1994); and Walker, Texas Ranger (1996). He also appeared in the Masterpiece Theatre presentation of Eudora Welty’s The Ponder Heart (2000) on PBS. In 2010, for its homage to Twin Peaks, Von Dohlen appeared in USA Network's show Psych in the episode Dual Spires, playing Sheriff Andrew Jackson joining a cast reunion including Sheryl Lee.
In 1992, he also played a government agent of a future fascist state in the BBC's Red Dwarf series V, episode 6, Back to Reality.
In the theater, Von Dohlen has created roles in the New York productions of Asian Shade, The Team, Twister, Vanishing Act, and The Maderati, the latter two by Richard Greenberg. For nine months he starred in Caryl Churchill’s play, Cloud , directed by Tommy Tune, followed by The Roundabout Theatre Company's revival of Desire Under the Elms, opposite Kathy Baker. He has starred in Hamlet, Romeo and Juliet, Joe Orton's Loot, Legacy of Light at Cleveland Play House, and in "Doubt" at the Indiana Repertory Theatre. On the West Coast, Von Dohlen has been seen in Wedekind's Lulu at the La Jolla Playhouse, and The Blue Room at the Pasadena Playhouse, Theater District at the Black Dahlia Theater. In Pasadena at The Theater @ Boston Court, Von Dohlen both originated the role of the famous literary personality Voltaire in the world premiere of Jean Claude van Italli's Light and played Don Quixote in Tennessee Williams's Camino Real. Most recently at GTC, he played Elyot Chase in Noël Coward's Private Lives.
Von Dohlen has a daughter named Hazel, born on 9 August 2000.