Donald Carter, 69, of West Philadelphia, a well-known and beloved activist in the gay community, died Monday, Feb. 25, of heart disease at his apartment, the Philadelphia Medical Examiner’s Office said.

A retired history professor at the University of Cincinnati, Mr. Carter kept a high profile in the city as a volunteer for Action Wellness, as a board member of the Jonathan Lax Clinic of Philadelphia FIGHT, and as founder and board member of the Philadelphia Chapter of the Log Cabin Republicans.

Action Wellness is an AIDS advocacy group. Philadelphia FIGHT is a community health and research center. The Log Cabin is a political action group.

But perhaps his best moment in the limelight occurred while he was a citizen panelist once on Bill Maher’s Politically Incorrect TV show, Suzi Nash, a columnist for the Philadelphia Gay News, reported.

“It gave me a national platform to say I’m gay and to represent Philadelphia,” Mr. Carter told Nash for a 2005 newspaper profile.

A Philadelphia native, Mr. Carter graduated from Central High School and Temple University. He earned a master’s degree in ancient Roman history from the University of Cincinnati, where he taught for several years. He started his AIDS activism by lecturing in small Ohio towns in the 1970s, Nash wrote.

When Nash asked what he did for a living, Carter answered: “The generic answer would be community activist.” But he told her his best job description was: “Be there. Do that.”

Chris Bartlett, executive director of the William Way LGBT Community Center, said Mr. Carter was known as “mayor of the Gayborhood” in Philadelphia because he showed up at every event sponsored by the gay and lesbian community. Often, he wore his signature suit and tie, sometimes with scarf or hat.

“You knew you had a successful event if Donald was there,” Bartlett said. “He was somebody who was deeply interested in Philadelphia’s arts and culture. He spent time getting to know people as he went from event to event.”

Mr. Carter was a major supporter of the John C. Anderson Senior Apartments, housing for, but not limited to, members of the aging gay, lesbian, bisexual, or transgender community.

The affordable-housing project won a competitive $11 million state tax credit in 2012, allowing construction to begin on a six-story building at South 13th Street between Spruce and Locust.

Mr. Carter said the facility was needed because men who were openly gay were having to return to the closet when they moved to mainstream assisted-living facilities because of expected prejudice.

“It would be nice,” Mr. Carter told the Inquirer in April 2012, “when one is approaching one’s dotage to have the comfort factor” of living in a nonjudgmental community.

“The system as it stands is not very accommodating,” he told the Associated Press for a December 2011 article. “I don’t really want to see any kind of negative attitude or lack of services because anyone’s gay or lesbian.”

Mark Segal, founder and publisher of the Philadelphia Gay News, said the housing project succeeded in part because Mr. Carter was candid about what it was like to be an aging gay man. Mr. Carter told of fearing a time when he wouldn’t be able to manage the stairs to his third-floor walk-up apartment. “We could not have had a better spokesperson,” Segal said.

Bartlett said Mr. Carter had diverse opinions and represented a time when people who disagreed reached across the political divide to find common ground. Mr. Carter, however, was kidded mercilessly by his friends for being affiliated with Republicans.

“He told me, ‘Somebody black and gay has to be a Republican, and that is me,’ ” Bartlett said. “He was warm and engaging.”

Mr. Carter is survived by a sister. A tribute and memorial will be at 1 p.m. Saturday, March 16, at the William Way LGBT Community Center, 1315 Spruce St., Philadelphia.