In 1969, she had her breakthrough film role in the sex comedy Bob & Carol & Ted & Alice, for which she was nominated for an Academy Award for Best Supporting Actress.

[5][6] In 1956, Cannon dropped out of college and went to live with her aunt Sally in Phoenix, Arizona, where she took a job at Merrill Lynch & Co.[7][8] Courted by nightclub owner Sonny Orling, then 32, she got engaged and followed him to Beverly Hills, California.

[10] In 1964 she guest-starred on Gunsmoke, playing Ivy Norton, an abused daughter looking to marry the man she loves in the episode "Aunt Thede".

Cannon also made guest appearances on 77 Sunset Strip, The Untouchables, Tombstone Territory, the 1960 episode "Sheriff of the Town" of the first-run syndicated western series Two Faces West with Walter Coy as Cauter and the 1962 Ripcord episode "The Helicopter Race" as Ripcord Inc.'s secretary and receptionist Marion Hines.

Cannon's first major film role came in 1969's Bob & Carol & Ted & Alice, which earned her Academy Award and Golden Globe nominations.

In 1971 she starred in four films: The Love Machine, from the novel by Jacqueline Susann; The Anderson Tapes with Sean Connery and Christopher Walken; The Burglars with Jean-Paul Belmondo and Omar Sharif; and Otto Preminger's Such Good Friends, for which she received a Golden Globe nomination for Best Actress.

Cannon was slated to appear in The Traveling Executioner (1970) and Double Indemnity (1973), but bowed out and was replaced by Marianna Hill and Samantha Eggar, respectively.

[11][12] In 1973, Cannon starred opposite Burt Reynolds in Shamus and played an agent based on Sue Mengers in The Last of Sheila, and was named Actress of the Year by the National Association of Theatre Owners.

[13] In 1974, she gave a critically acclaimed performance in Child Under a Leaf and starred in the made-for-TV movie Virginia Hill with Harvey Keitel.

[15] Cannon starred in her own musical stage act at Caesar's Palace in Las Vegas and Harrah's Lake Tahoe during the mid-1970s.

She became the first Oscar-nominated actress to be nominated in the Best Short Film, Live Action category for Number One (1976), a project which Cannon produced, directed, wrote and edited.

That same year, she appeared in Heaven Can Wait, for which she received another Oscar nomination and won a Golden Globe Award for Best Supporting Actress.

[22] She subsequently appeared opposite Phylicia Rashad in Jailbirds (1991) and Kris Kristofferson and Tony Curtis in Christmas in Connecticut (1992), the latter of which was directed by Arnold Schwarzenegger, before reuniting with Bob & Carol & Ted & Alice director Paul Mazursky for The Pickle (1993), alongside Danny Aiello.

In 1997 she could be seen in three major studio film releases: 8 Heads in a Duffel Bag with Joe Pesci; a remake of That Darn Cat; and Out to Sea with Walter Matthau and Jack Lemmon.

In 2005, she appeared in Boynton Beach Club, a movie about aging Floridians who have just lost their spouses; Cannon's real-life ex Michael Nouri played her love interest.

Her later roles included A Kiss at Midnight (2008) for Hallmark and the unaired pilot Women Without Men (2010) with Lorraine Bracco and Penny Marshall.

[25] She had previously been approached by Swifty Lazar to write about her late ex-husband in 1986, turning down "millions," and declined another publishing offer some years later from Jacqueline Kennedy Onassis, stating that there was still healing that needed to happen.

[32] Cannon has also been in relationships with comedian Mort Sahl, talent agent Ron Weisner and sculptor Carl Hartman, as well as producers Murray Shostak and Leonard Rabinowitz, directors Hal Ashby and Jerry Schatzberg, and actors Armand Assante, Hy Chase, Ron Ely and Michael Nouri.

Shostak and Rabinowitz produced her starring vehicles Child Under a Leaf and The End of Innocence respectively; Schatzberg directed her in Honeysuckle Rose; Assante and Nouri were her leading men in Lady of the House and Boynton Beach Club respectively; and she guest-starred on Ely's series Malibu Run.