She also made an appearance as a guest on the television program The Tonight Show originating from New York, hosted at the time by Jack Paar. By 1965, Rivers had a stint on Candid Camera as a gag writer and participant; she was "the bait" to lure people into ridiculous situations for the show. After seven auditions during a period of three years, she made her first appearance on The Tonight Show with new host Johnny Carson, on February 17, 1965. Rivers credited this episode to be her breakthrough, as Carson said to her on the air "you're gonna be a star". Following this appearance, she became a frequent guest on the program and a close friend of Carson.
In early 1965, at the suggestion of comedian Bill Cosby, Johnny Carson gave Rivers, whom he billed as a comedy writer, her debut appearance on his show. Cosby, who knew Rivers from their early stand-up days, described her as "an intelligent girl without being a weirdo...a human being, not a kook." Sitting alongside Johnny after her monologue, she displayed an intimate, conversational style which he appreciated, and she was invited back eight more times that year. Time magazine compared her humor to that of Woody Allen, by expressing "how to be neurotic about practically everything", but noting that "her style and femininity make her something special." Rivers also compared herself to Allen, stating: "He was a writer, which I basically was...and talking about things that affected our generation that nobody else talked about." The New York Times critic Charles L. Mee likewise compared her to Allen, explaining that her "style was personal, an autobiographical stream-of-consciousness."
Rivers married Edgar Rosenberg on July 15, 1965. Their only child, Melissa Rivers, was born on January 20, 1968. Joan Rivers had one grandson, Cooper, born Edgar Cooper Endicott in 2000. Along with his mother and grandmother, Cooper was featured in the WE tv series Joan & Melissa: Joan Knows Best? Rivers was married to Rosenberg until his suicide in 1987, four days after she asked him for a separation. She would later describe her marriage to Rosenberg as a "total sham", complaining bitterly about his treatment of her during their 22-year marriage. In a 2012 interview with Howard Stern, Rivers said she had several extramarital affairs when married to Rosenberg, including a one-night affair with actor Robert Mitchum in the 1960s and an affair with actor Gabriel Dell. In the 1990s, she was in an eight-year relationship with the commissioner of the New York State Office of Parks and Recreation, disabled World War II veteran Orin Lehman of the Lehman family.
Rivers was open about her multiple cosmetic surgeries and had been a patient of plastic surgeon Steven Hoefflin since 1983. She had her nose thinned while still at college; her next procedure, an eye lift, was performed in 1965 (when she was in her 30s) as an attempt to further her career. When promoting her book, Men Are Stupid...And They Like Big Boobs: A Woman's Guide to Beauty Through Plastic Surgery, described by The New York Times Magazine as "a detailed and mostly serious guide to eye lifts, tummy tucks and other forms of plastic surgery", she quipped: "I've had so much plastic surgery, when I die they will donate my body to Tupperware."