He rose to prominence during the mid-1980s for his work in such gay adult films as Winner Takes All, Below The Belt and In Your Wildest Dreams.

O'Hara wrote four books: SeXplorers: The Guide to Doing It on the Road, Do It Yourself Piston Polishing (for Non-Mechanics), Autopornography: A Memoir of Life in the Lust Lane, and Rarely Pure and Never Simple: Selected Essays of Scott O'Hara, and edited and published the quarterly men's sex journal Steam and the cultural magazine Wilde.

He edited and published from 1993 to 1995 the quarterly men's journal Steam, "the intellectual review of public sex", intended to facilitate cruising.

Articles often featured rest room, park, and other risky sexual encounters, and every issue contained tips on cruising spots (public places to meet men for sex), with notes on their safety or lack of same.

"[8] Returning to San Francisco in 1995, he published five issues of the short-lived cultural magazine Wilde; he also contributed to a number of other publications.

[9] Upon his death, he left his personal papers (consisting of 39 boxes of journals, correspondence, notes, and manuscripts) to the John Hay Library of Brown University.

The archives of the GLBT Historical Society in San Francisco preserve a collection of O'Hara's performance costumes and other memorabilia.

[10] The sibling to whom he had been closest was the lesbian activist and poet Claudia (Ann) Scott, who left him the poem For My Youngest Brother.

[12] He said he was "obsessed with anything sexual" as young as eleven,[13] and that his first sex with another man took place when he was fifteen, when he seduced, or perhaps raped (the word is his), a twenty-eight-year-old.

He claimed to enjoy the scene and was proud of his butch appearance in the role, writing that "in all my years of ass-pounding, I'd never once gotten into a pussy, and I felt as if this were a serious gap in my sexual education, which needed filling.

[26][27] His trust fund exhausted, O'Hara spent his final years in a windowless San Francisco apartment[28] he called "The Cave", surrounded by his record albums, CDs, books, and erotic art, and occupied his time gardening.