Alan Khazei, touting the endorsement of Max Kennedy and his wife Victoria, portrayed himself today as the change agent in the race for the US Senate seat of the late Edward M. Kennedy.

The co-founder of the Boston nonprofit City Year, who has never run for any office before, said his background is suited to the times. He said he knows how to push legislation through Congress — he helped pass several laws dealing with public service — but added that he is not beholden to the Washington power structure. He promised not to accept any lobbyist or political action committee money because special interests “are polluting our system.”

“Congress is stuck and that’s why I’m running. I know how to get change,” Khazei said.

Khazei’s liberal politics don’t seem to differ much from his rivals in the Democratic primary — Attorney General Martha Coakley, Congressman Michael Capuano, and businessman Stephen Pagliuca. Coakley and Capuano have the most name recognition among Massachusetts voters, and Pagliuca has a personal fortune to spend. Khazei is raising money as fast as he can and trying to tap into the idealism of the young voters who have participated in his public service initiatives.

Max Kennedy, the son of Robert F. Kennedy and the nephew of Edward M. Kennedy, said he felt compelled to endorse Khazei even though Khazei is a political unknown with no money and no idea about how to run a political campaign. The Los Angeles resident also said he wanted to stay as far as possible from the race for his uncle’s US Senate seat.

“I’ve never come out for a candidate in a Democratic primary in my life, and I really didn’t want to do it in this race,” Kennedy said at an event at the Parker House Hotel in Boston. But he said he has been friends with Khazei for about 20 years and believes he is the best person for the job. “We need real change in this state and across the country,” he said.

Kennedy, a Los Angeles author who has written extensively about suicide as a weapon of war, made several campaign appearances with Khazei in Boston and on area college campuses.

Bruce Mohl oversees the production of content and edits reports, along with carrying out his own reporting with a particular focus on transportation, energy, and climate issues. He previously worked...