She made her film debut in the Civil War-themed drama Shenandoah (1965), and had supporting parts in Mister Buddwing and The Singing Nun (both 1966) before being cast in Curtis Harrington's Games (1967), a thriller co-starring James Caan and Simone Signoret.

She garnered further acclaim for her roles in two 1969 Westerns: Butch Cassidy and the Sundance Kid and Tell Them Willie Boy Is Here, for both of which she won the BAFTA Award for Best Actress.

Ross spent the majority of the 1980s appearing in a number of made-for-TV films, including Murder in Texas (1981) and The Shadow Riders (1982), and later starred on the network series The Colbys from 1985 to 1987.

In 2016, she provided a voice role for the animated comedy series American Dad!, and the following year starred in the comedy-drama The Hero (2017), opposite her husband, Sam Elliott.

[14][15] Ross's mother, the former Katharine Elizabeth Washburn[16][17] (née Hall;[18] 1909–1993),[19] was born in Indianapolis and later moved to the San Francisco Bay Area.

[27] Ross transferred to Diablo Valley College in 1958, and starred in a student film by Jim and Artie Mitchell (of O'Farrell Theatre fame).

[32][33] She was signed by agent Wally Hiller,[34] and in 1964, Ross appeared in episodes of Kraft Suspense Theatre, The Lieutenant, Arrest and Trial, The Virginian, The Great Adventure, Ben Casey, Mr. Novak, Wagon Train, Bob Hope Presents the Chrysler Theatre, Run for Your Life, Gunsmoke, and The Alfred Hitchcock Hour ("Dividing Wall", 1963), as well as playing the love interest of Heath Barkley opposite Lee Majors on The Big Valley (season one, episode seven-"Winner Loses All").

She signed a long-term deal with Universal, which called her an "American Samantha Eggar",[36] despite some misgivings: "I didn't want a contract in the movies, but a lot of people convinced me it was a good thing to do.

[32] At Universal, Ross starred in a television film with Doug McClure, The Longest Hundred Miles (1967),[24][37] then co-starred in Curtis Harrington's psychological thriller, Games (1967) with Simone Signoret and James Caan, which she later called "terrible".

[38] Ross's breakthrough role was as Elaine Robinson in Mike Nichols's comedy-drama The Graduate (1967), opposite Dustin Hoffman and Anne Bancroft.

Ross was cast as a Native American woman in Universal's Western film Tell Them Willie Boy Is Here (1969), starring Robert Redford.

[45] She was dropped by Universal in the spring of 1969 for refusing to play a stewardess in Airport starring Burt Lancaster and Dean Martin, another role that went to Jacqueline Bisset.

[37] She occasionally acted, appearing in Get to Know Your Rabbit (1972), They Only Kill Their Masters (1972), which reunited her with James Garner, and Chance and Violence (1974) with Yves Montand.

[43] Ross subsequently appeared in the drama film Voyage of the Damned (1977) about a doomed ocean liner carrying Jewish refugees from Nazi Germany, which earned her a second Golden Globe Award for Best Supporting Actress.

Next, Ross co-starred opposite Sam Elliott in the supernatural horror film The Legacy (1978), playing a woman who finds herself subject to an ancestral curse at an English estate.

[54] Ross co-wrote the teleplay and starred in Conagher (1991) alongside husband Sam Elliott and was in A Climate for Killing (1991), and Home Before Dark (1997).

[57] After completing Butch Cassidy and the Sundance Kid, Ross married the film's cinematographer, three-time Oscar-winner Conrad Hall, in 1969.