Van Ark attended the Yale School of Drama, reportedly as one of the youngest students ever. After graduating, she appeared with the prestigious Guthrie Theatre in Minneapolis. Her big break came when she was tapped to replace Elizabeth Ashley as the idealistic, free-spirited female lead of Neil Simon's "Barefoot in the Park" on Broadway and on tour. In 1971, Van Ark earned a Tony nomination for Best Featured Actress in a Play for her work in "The School for Wives". Following that success, she moved to L.A., but periodically returned East to appear on stage. Van Ark worked summers at the Williamstown Theatre Festival and in 1995 replaced Marian Seldes in Edward Albee's Pulitzer Prize-winning "Three Tall Women". She co-starred with her daughter Vanessa Marshall in the 1997 L.A. production "Star Dust".
Van Ark began to travel West in the late 1960s and established a toe-hold on the small screen. In 1968, she appeared in episodes of "The Guns of Will Sonnet", "The Mod Squad" and "Gunsmoke." She had her first regular series work as a sexy nurse on the first season of the ABC sitcom "Temperatures Rising". On the short-lived CBS sitcom "We've Got Each Other" (1977-78), she was hilarious as a self-involved model. Throughout the 70s, Van Ark made numerous guest appearances in key roles on series: In a 1975 episode of "Rhoda" she played the first wife of Rhoda's husband while in a 1977 episode of "Kojak" she was the first woman cop in the squad room. TV-movies like "The Judge and Jake Wyler" (NBC, 1972) and miniseries like the syndicated "Testimony of Two Men" (1977) also provided work.
Cast in 1978 as the fragile Valene Ewing, the wife of black sheep Gary, on the CBS primetime serial "Dallas", Van Ark found what was to become her signature role. Val and Gary were originally to be the anchors of the spin-off series, "Knots Landing". Over the long run of the show, the focus changed, but the characters remained integral to the plot. Van Ark was given the opportunity to work with her idol, Julie Harris, who played her mother, and a rising actor, Alec Baldwin, was cast as her brother. As with several of the regulars, she was also given the opportunity to direct episodes. Because of her strong voice--she could have been a news anchor--and presence, Van Ark found herself acting as host for CBS specials like the Tournament of Roses Parade and both the Miss USA and Miss Universe pageants.
Of course, the inevitable TV-movie roles came as well. Van Ark was the wife of test pilot Barry Bostwick in "Red Flag: The Ultimate Game" (CBS, 1981), played famed 40s Hollywood madam Brenda Allen in "Shakedown on the Sunset Strip" (CBS, 1988), portrayed a power-made PTA president in "Menu for Murder" (CBS, 1980) and was Stephen Dorff's adopted mother from whom he flees to find his real mother in "Always Remember I Love You" (CBS, 1990). In 1993, Van Ark was executive producer of "In the Shadows, Someone's Watching" (NBC), and in 1994, played a wife and mother who becomes a fanatical cult member in "Moment of Truth: A Mother's Deception" (NBC). She directed "Boys Will be Boys", a 1994 "ABC Afterschool Special" about a girl who finds her reputation besmirched by innuendo and scribblings on the lavatory wall. She reprised her most famous role in "Knots Landing: Back to the Cul-De-Sac" in 1997.
Additionally, Van Ark leant her unique vocal talents to a number of TV commercials (for perfume, automobiles, etc.) and numerous animated projects She was the voice of the comely Roxanne in the 1975 ABC version of "Cyrano" and a lead voice in "Batman and the Super Seven" in 1980. More recently, she was a seductive insect in the CBS animated series "Santo Bugito" (1995-96).