She was born in San Francisco, California. In 1940, her family moved to Los Angeles. Her father was an executive with United Press. Her mother was a minister. Powers later told a reporter, “I’ve worked in show business since I’ve been seven.” In the summer of her relocation, Powers attended the Max Reinhardt Junior Workshop where she enjoyed her first role in a play before a live audience. She continued with her drama lessons, and a year later she auditioned and won a part in the 1942 Little Tough Guys film Tough as They Come. At the age of 16, Powers began working in radio drama, before becoming a film actress in 1950. Powers first movie roles were in Outrage and Edge of Doom in 1950. That same year, Stanley Kramer signed Powers to star opposite Jose Ferrer in what may be her most remembered role as Roxane in Cyrano de Bergerac. She was nominated for a Golden Globe Award for her part in this movie.  While on a USO entertainment tour in Korea in 1951, she acquired a blood disease and nearly died. She was treated with chloromycetin, but a severe allergic reaction resulted in the loss of much of her bone marrow. Powers barely survived, and her recovery took nearly nine months. She began working again in 1952, including the lead in Rose of Cimarron (1952) and co-starring roles in City Beneath the Sea (1953) and City That Never Sleeps (1953), although she was still taking medication. Following her recovery, she appeared in B-movie westerns, such as Rage at Dawn (1955), The Storm Rider (1957) and Sierra Baron (1958), and science fiction films, among them The Unknown Terror (1957), The Colossus of New York (1958), Flight of the Lost Balloon (1961), and Doomsday Machine (1972). She also had large roles in Tammy and the Bachelor (1957) and Daddy’s Gone A-Hunting (1969).

She appeared in more than one hundred television series episodes, including Appointment with Adventure, Crossroads, The Restless Gun, Bourbon Street Beat, The Rebel, Maverick (in an episode called “Dutchman’s Gold” with Roger Moore), The Everglades, Bonanza, Mission: Impossible, Bewitched, The Wild Wild West, The Silent Force, Cheyenne episodes “Alibi for the Scalped Man” (1960) and “Trouble Street” (1961), and in the Wanted: Dead or Alive episode “Till Death do us Part”, with Steve McQueen. In 1962, she portrayed the part of Loretta Opel, a woman with leprosy, in the episode “A Woman’s Place” on CBS’s Rawhide. On CBS’s Perry Mason, she played defendant June Sinclair in the 1960 episode, “The Case of the Crying Cherub.” Her most memorable role was as defendant Susan Brent, friend of Perry’s secretary Della Street (Barbara Hale) in the 1962 episode “The Case of the Weary Watchdog.” In 1964 she portrayed murderer Helen Bradshaw in “The Case of the Frightened Fisherman,” and in 1966 she played murder victim Elaine Bayler in “The Case of the Scarlet Scandal.” In 1971, Powers was cast, along with Mike Farrell and June Lockhart, opposite Anthony Quinn in the first of the fifteen episodes of the NBC television series The Man and the City. Powers was a successful children’s author of Follow the Star and Follow the Year and Dial a Story. She also revised and edited two books by Edin Blyton after the author’s death. Powers died from complications of leukemia on June 11, 2007, at Providence St. Joseph Medical Center in Burbank, California. She was survived by her son, Toren Vanton. Shortly before her death, she had been on a lecture tour at universities. She was patron of the Michael Chekhov Studio London and has a star on the Hollywood Walk of Fame at 6360 Hollywood Boulevard.