Judd Marmor was born in London, England, in 1910, the son of a Yiddish scholar. He grew up in Chicago, and later moved to New York, where he supported himself through Columbia College with odd jobs and debating scholarships. He earned his medical degree from Columbia College of Physicians and Surgeons in 1933, and went into private psychiatric practice in New York. In 1946, after serving in the Navy during World War II, he moved to Los Angeles, where he gained prominence as an analyst to Hollywood celebrities. He was also widely respected as an analyst and scholar, publishing more than 350 papers and writing or editing six books, including the classic text , first published in 1968. He served as director of the psychiatry division at Cedars-Sinai Medical Center from 1965 to 1972. From 1972 to 1980 he was Franz Alexander Professor of Psychiatry at the University of Southern California, and from 1980 to 1985 adjunct professor of psychiatry at the University of California at Los Angeles.

Marmor had begun to treat homosexual patients who wanted to change their orientation in the 1940s. Although he originally held the belief that homosexuality was an illness, his clinical experiences with gay patients and later his social interactions with gays who were happy with their lives and emotionally well-adjusted convinced him that homosexuality was not pathological. His view was supported and influenced by the Evelyn Hooker's groundbreaking study, published in 1957, which found no measurable psychological difference between heterosexual and homosexual men. Marmor asked Hooker to write a chapter for his first book on homosexuality, , published in 1965; she in turn recruited him for the National Institute of Mental Health Task Force on Homosexuality in 1969. The two became close colleagues and friends, often lecturing together.

The evolution of Marmor's view of homosexuality as a normal condition coincided with the growth of gay and lesbian activism. At the 1972 annual convention of the American Psychiatric Association in Dallas, Marmor, then Vice President of the organization, participated in a dramatic presentation with fellow psychiatrist Robert Seidenburg, gay activist Franklin Kameny, lesbian activist Barbara Gittings, and a gay psychiatrist wearing a mask and identifying himself as "Dr. H. Anonymous". The following year, Marmor played a critical role in the campaign to remove homosexuality from the American Psychiatric Association's . The issue was so controversial that it was placed before the full membership, which adopted the resolution to remove homosexuality from the Manual in a split vote in December 1973. The removal of homosexuality from the list of mental disorders was one of the single most important events in the modern history of the gay movement, and by taking away part of the basis for disparaging and belittling gays and lesbians was crucial in breaking down other barriers.

Marmor continued to see patients until shortly before his death. He also served for many years as advisor to Abigail Van Buren, who wrote the "Dear Abby" newspaper column and was one of the first national figures to support gay rights. He and his wife were also serious collectors of art, lending and giving many artworks to the Los Angeles County Museum of Art and the Museum of Contemporary Art in Los Angeles. He died in Los Angeles at the age of 93, on December 16, 2003, a day after the 30th anniversary of the American Psychiatric Association's vote to remove homosexuality from its Diagnostic Manual.

Source: Obituary by Elaine Woo, , December 20, 2003, p. B20.