The social entrepreneur has struggled to sustain his campaign given the immense excitement, political heft and financial support that has coalesced around Elizabeth Warren, who entered the race in September.

Alan Khazei, at one point favored to win the Democratic primary to challenge US Senator Scott Brown next year, is withdrawing from the race.

Khazei spokesman Scott Ferson said the City Year co-founder will make his exit official at his campaign headquarters at noon tomorrow.

Since Warren, a Harvard Law professor and former Obama administration consumer advocate, entered the race, Khazei, 50, has struggled to raise money, and seen his political support wane.


“She has struck a chord, no doubt about it,” Khazei said in an interview this morning. “It’s definitely affected my position. So fundraising has been tougher, and in terms of attention … It’s challenging. Things have definitely shifted.”

Since Warren entered the race, Khazei has struggled for media attention, too. He also came under scrutiny for hiring his brother as a consultant to his charity, Be The Change. He said the unflattering coverage wasn’t a factor in his thinking about whether to stay in the race.

Until Warren declared her candidacy, national Democrats made no secret of their disappointment in the field that had formed to challenge Brown, and they aggressively pushed the consumer advocate to run. But Khazei said they had not directly pressured him to drop out.

Khazei placed third in the Democratic primary in the special election for the seat held by the late Senator Edward M. Kennedy in 2010. He said he got into the race this time because he believes Brown, the Republican who won that seat, has “failed us as a leader,” and because he wanted to make sure the incumbent is turned out of office next year.

“I don’t want to do anything that is going to stop that from happening,” Khazei said.


Just a couple of weeks ago, after Newton Mayor Setti Warren and Somerville activist Bob Massie dropped out of the race, a Khazei spokesman said his candidate would not step aside, though it was clear Khazei had begun to struggle to raise money. The struggle grew harder, however.

“Alan always knew there would be an establishment candidate in this race,” Ferson said. “He did not prepare for these dynamics, with the money drying up.”

Khazei would not confirm he was withdrawing from the race in the interview earlier today, but it was clear he was weighing his decision, and thinking about his future.

“You don’t have to be a candidate to be involved in politics,” he said. “I’m committed to staying in the arena and pushing for a different kind of politics.”

In addition to Elizabeth Warren, his departure leaves just four Democrats in the race, none of whom have Khazei’s profile or campaign funds: Marisa DeFranco, a North Shore immigration attorney; Herb Robinson, a Newton engineer; Thomas P. Conroy, a state representative from Wayland; and James C. King, a Dover lawyer.

Yvonne Abraham is a Globe columnist. She can be reached at Abraham@globe.com