Comedian Bill Cosby joined hundreds of Harvard Medical School (HMS) alums Saturday to honor famed civil rights activist and Professor of Psychiatry Alvin F. Poussaint, in an extensive all-day tribute.

Poussaint, who serves as Associate Dean for Student Affairs at HMS, has been on the cutting edge of the mental health field since the 1960s. A pioneer in the civil rights movement, Poussaint is best known for linking issues of racial inequality with the practice of psychiatry and served as a field medic at two of Martin Luther King Jr.’s demonstration marches through Mississippi.

Poussaint served as a consultant to the Cosby Show’s writing team during the sitcom’s entire eight-year run, and has remained a close personal friend of Cosby since the show’s premiere in 1984.

Poussaint was instrumental in the racial integration of HMS in the 1970s, working together with the dean of HMS and then-Harvard President Derek C. Bok. He has written several groundbreaking books, maintaining throughout his career that widespread racial discrimination in America is one of the leading causes of mental illness among minorities. According to the countless tributes addressed to Poussaint on Saturday, the professor has inspired hundreds of young doctors and psychiatrists who would have otherwise felt alienated in the early days of the medical school’s integration efforts.

Saturday’s celebration, which began with a research symposium in the HMS Armenise Amphitheatre and ended with an extravagant dinner party at the Westin Hotel in Copley Square, was planned around the launch of the Alvin F. Poussaint, MD Lecture Fund, a program that will bring speakers to HMS who specialize in minority issues in medicine and psychiatry.

In his afternoon address, Poussaint focused on nonviolence as a means of promoting mental health and racial harmony, saying that “wars and killing and violence make a mockery of health care.”

“I sit around Harvard and I see all the research going on to prolong life,” he said. “All of that effort is being destroyed by bombs, bullets, and high tech armaments which threaten to destroy all of us.”

The daytime program concluded with a chorus of “We Shall Overcome,” which the audience sang in a three-part round at the direction of the professor.

While Cosby did not attend the afternoon proceedings, he did perform a forty-minute comedy routine at the evening dinner party. Speaking in his famously slow and contemplative drawl, Cosby played to the crowd, riffing on the medical profession, his fear of vaccinations, and the hilarious perils of old age.

“First of all, the hospital has a smell,” he said, pacing back and forth on the stage. “You can walk into places like the swimming pool and you smell chlorine. But I mean, the hospital has a smell of putting people to sleep. Even when you’re little you recognize this.”

Folk singer James Taylor and Poussaint’s brother-in-law Owen Young, a cellist from the Boston symphony, served as the evening’s opening act, playing two songs before handing the stage over to Cosby.

Camille E. Powe ’06 said she had had to beg her father, an HMS graduate who donated $1,000 to the Lecture Fund, to bring her to the event before he agreed to buy her a ticket.

Poussaint’s family was in attendance throughout the day, many of them circling the floor of the Westin’s American Ballroom and exchanging pleasantries with old friends and alumni. Poussaint himself could be seen posing for camera phone photos at the request of his many admirers.

The professor’s older brother Clement, a former secret service bodyguard for Robert F. Kennedy ’48 and George H.W. Bush, arrived at the afternoon luncheon with his fiancée of ten years, Etta Dixon, who pointed out that “Alvin had lost weight” as the professor passed by her table with his wife.