The newly divorced Phillips landed her first film role in Dennis Hopper's all-but-unwatchable "The Last Movie" (1970) set in the jungles of Peru. Although she spent eight days married to Hopper, Phillips hardly made an impression in her debut. She fared somewhat better as the moll to Warren Oates' "Dillinger" (1973) and slowly began to make inroads as a guest performer on the small screen. Phillips looked smashing as the lesbian Natasha Rambova holding power over "Valentino" (1977) in Ken Russell's extravagant biopic and held her own opposite James Mason in "Bloodline" (1979). She later portrayed the mother of gymnast Mitch Gaylord in the underperforming "American Anthem" (1986) and was relegated to forgettable fare in the 90s (i.e., "Scissors" 1991; "Army of One" 1993).
But the small screen proved more receptive and Phillips earned, if not superstardom, status as a working actor. Among her early roles were as love interest to Robert Forster and daughter to Melvyn Douglas in the faux-Eastwood TV offering "The Death Squad" (ABC, 1974) and the female lead in "The California Kid" (ABC, 1974). In 1977, she was featured in the NBC miniseries "Aspen" and the following year lent her allure to the role of the sexual plaything daughter of a fading movie star (Tony Curtis) in "The Users" (ABC). Phillips has been tagged by executive producer Jay Bernstein for several "Mickey Spillane" TV-movies, including "Murder Me, Murder You" (CBS, 1983), and "Murder Takes All" (CBS, 1989). By the mid-80s. the actress landed her first recurring role on a series as Elizabeth Bradshaw Cabot, a nemesis for manager James Brolin in "Hotel" (ABC). But it was her stint as the conniving vixen and perpetual loser Anne Mathison on the CBS serial "Knots Landing" that solidified her reputation. She originated the part in 1987 and returned to it from 1990 to 1993, reprising the role in the reunion movie "Knots Landing: Back to the Cul-de-Sac" (CBS, 1997). Phillips had less luck in her subsequent series, both of which were short-lived ("Second Chances" CBS, 1993-94, and "Malibu Shores" NBC, 1996). More recently, she was seen in the recurring role of mother to Valerie Malone (Tiffani-Amber Thiessen) on Fox's "Beverly Hills, 90210".