A native of Long Beach, California, she spent her early life in Los Angeles and Mexico City, raised by her widowed father.

While working as a model in San Francisco, she met and married John Phillips in 1962 and went on to co-found the vocal group the Mamas & the Papas in 1965.

After the breakup of the Mamas & the Papas and her divorce from John Phillips, she transitioned into acting, appearing in a supporting part in The Last Movie (1971) before being cast as Billie Frechette in the critically acclaimed crime biopic Dillinger (1973), for which she was nominated for a Golden Globe Award for Most Promising Newcomer.

In 1974, she had lead roles in two television films: the crime feature The Death Squad, and the teen drama The California Kid, in the latter of which she starred opposite Martin Sheen.

She went on to appear in a number of films throughout the remainder of the 1970s, including Ken Russell's Valentino (1977), playing Natacha Rambova, and the thriller Bloodline (1979).

The next year she co-starred with Tom Skerritt in the nature-themed horror Savage Harvest (1981), followed by the television films Secrets of a Married Man (1984) and The Covenant (1985).

Phillips appeared in independent films in the 2000s, with supporting parts in Jane White Is Sick and Twisted (2002) and Kids in America (2005) and had recurring guest roles in the television series That's Life (2001–2002) and 7th Heaven (2001–2004).

[8] Her mother suffered heart problems stemming from a childhood bout with rheumatic fever, including subacute endocarditis,[9] and died of a related brain hemorrhage when Phillips was five years old.

[10] Reflecting on her mother's illness, Phillips said: "They knew it was only a matter of time ... She would lie on the couch in the evenings, listening as my father read to her.

"[9] Following his wife's death, Phillips's father, wanting a change of scenery, relocated the family to Buffalo, New York, where they lived for nine months while he worked as a bartender.

[15] Phillips recalled that her and her sister's experiences living in a different culture "helped us get over my mother's death, and instead of grieving, we became very strong, independent, and free".

[21] Phillips quickly became immersed in San Francisco's countercultural music scene and nightlife, recalling: "Tamar and I loved going out and showing off.

"[22] At a club in San Francisco in July 1961, she met John Phillips while he was touring California with his band the Journeymen, and the two began a whirlwind romance.

[25] Michelle co-wrote some of the band's hits, including "California Dreamin'", which appears on the group's debut album, If You Can Believe Your Eyes and Ears (1966).

[33] However, she was rehired on August 23 after the remaining band members concluded that her replacement, Jill Gibson,[34] lacked her predecessor's "stage charisma and grittier edge".

[35][36] After Phillips's reinstatement, the band embarked on a brief tour of the East Coast, playing a series of shows in Washington, D.C., Baltimore, and at Fordham University in New York City.

Everybody in that movie was a real actor: Warren Oates, Ben Johnson, Cloris Leachman, Richard Dreyfuss, Harry Dean Stanton.

Phillips released her first solo single in 1976, "No Love Today", which appeared on the Mother, Jugs & Speed movie soundtrack.

[61] The same year, she recorded the song Forever for the movie soundtrack of California Dreaming, a surf film unrelated to her former group despite its title.

On television, Phillips played the mermaid princess Nyah in three episodes of Fantasy Island and Leora Van Treas in Mike Hammer: Murder Takes All (1983), starring Stacy Keach in the title role.

[69] In it, she describes events such as her first meeting with Cass Elliot, winning 17 straight shoots at a craps table in San Juan, Puerto Rico when the band was broke and could not afford the airfare back to the United States mainland, and how her writing credit on "California Dreamin'", which still nets her royalties, was "the best wake-up call" she ever had; she was asleep in a New York hotel room when husband John Phillips woke her to help him finish the new song that he was writing.

[71] Phillips was a passenger in the car with boyfriend Geoffrey Tozer, and the marijuana was discovered after police searched the couple's vehicle.

[76] While starring on Knots Landing, Phillips continued to appear in films, including a supporting role in 1989's gambling-themed Let It Ride, co-starring with Richard Dreyfuss and Teri Garr, playing what Kevin Thomas of the Los Angeles Times characterized as a "deliciously blonde society tramp".

[66] Following the 1993 conclusion of Knots Landing, Phillips starred in the short-lived drama series Second Chances (1993–1994) opposite Connie Sellecca and Jennifer Lopez.

[79] She also had the lead role in the 1993 television thriller film Rubdown, playing a woman at the center of a divorce plot in which her husband pays a masseur to have an affair with her.

[80] Denise McIver of Variety panned the film, writing: "The most disturbing thing about this two-hour cable telefilm is its cynicism and the fact that none of the characters seemed redeemed, or at least changed, by their experiences.

This is not to say it won't hold one's interest, if only for the scenario, which delivers lots of bare backs, naked legs and superficially steamy sex scenes.

"[80] In late September 1993, Phillips and her friend Aloma Ichinose were robbed at gunpoint outside a restaurant in West Hollywood, California.

[91] Despite having received critical acclaim for her singing, Phillips has admitted to being self-conscious about her voice, and stated that Cass Elliot encouraged her during their tenure in the Mamas & the Papas.

'"[1] During a 1991 interview with Arsenio Hall, Phillips advocated providing teenagers with a pragmatic education on drugs, specifically to distinguish psychedelics and marijuana from more addictive substances such as cocaine and heroin.