Heilman was active in the incorporation of the City of West Hollywood. He was elected to the city's first city council in November 1984, and has served almost continuously since then.[4] Heilman lost re-election in March 2015, but months later won a special election to fill a seat vacated by Jeff Prang, who resigned to become L.A. County assessor. John Heilman was chosen as the city's second mayor in 1985, and also served as mayor in 1990, 1995, 1999, 2001, 2006, 2010 and 2017. He served his most recent term as mayor in April, 2017.
Heilman was defeated in his bid for re-election in November 2020. He was re-elected to the West Hollywood City Council in November 2022.[5]
Since his earliest days on the city council, one of Heilman's main concerns has been domestic partner rights. Heilman was instrumental in the establishment of West Hollywood's domestic partnership registration program that permitted city employee partners to register and obtain domestic partner benefits for same-sex couples and seniors, regardless of gender, who are at least 62.5 years old and living together.
Openly gay,[6][7] Heilman is also the past president of the Gay, Lesbian and Bisexual Local Officials Group and past co-chair of the International Network of Lesbian and Gay Officials. His 2007 re-election campaign has won the support of the Gay & Lesbian Victory Fund. He holds an active membership of the Stonewall Democratic Club. Heilman is also a member of the Coalition for Economic Survival.
As a result of Heilman's leadership on the issue of AIDS, he received the U.S. Conference of Mayor's Award in 1990.