In 1973, O'Connor sang the title song for the film Jeremy in which she also co-starred with Robby Benson. On January 8, 1974, she starred in the CBS Radio Mystery Theatre production of "Ring of Roses" and then co-starred with John Travolta in the 1976 made-for-television movie The Boy in the Plastic Bubble. That same year she portrayed the character Bobbie Lee Hartley, co-starring once again with Robby Benson, in the film Ode to Billy Joe, a tragic romance produced and directed by Max Baer, Jr.

In 1984, O'Connor co-starred with Armand Assante in the made-for-TV movie Why Me?, a drama about a United States Air Force nurse named Leola Mae Harmon, who must undergo a series of facial reconstruction surgeries after a horrifying car accident. She was cast too in 1984 in the comedy Johnny Dangerously, along with Michael Keaton, Peter Boyle, and Joe Piscopo. In 1986, O'Connor performed in the NBC made-for-TV movie The Deliberate Stranger with Mark Harmon.

From the late 1990s through 2004, she had a recurring role as Anne Paulsen on Law & Order. In 2007 she co-starred with John Heard, Vincent Pastore, and Robert Picardo in the independent feature film P.J., directed by Russ Emanuel. She appeared too in the film Our Last Days as Children.