As chairman of the Queens County Democratic Party, Mr. Crowley directed a party apparatus that held the power to make or break candidates through endorsements and nuts-and-bolts campaign help. He helped make the careers of many, including a who’s who of elected leaders who packed his victory-party-turned-political-wake on Tuesday night. He helped to elevate others to perches they might not otherwise have reached.

But faced with an energetic challenge for the first time in years, he could not help himself.

The loss sent reverberations throughout local races.

Insurgent candidates running for state offices and those who have bucked the county organization in the past rejoiced. Party officials licked their wounds and privately bemoaned the defeat by an upstart challenger who dared to run a primary campaign.

The aftermath could also be seen in more public gestures: On Thursday, the Council speaker, Corey Johnson, announced he would back four upstart challengers to Democratic incumbents in State Senate primary races this September. Mr. Johnson said the endorsements had been planned before Tuesday’s election results were known. But it was a move that Mr. Johnson might not have done in such an overt way out of deference to Mr. Crowley, whose support was critical in landing Mr. Johnson his role as speaker.

“Clearly the Democratic base is extremely angry, hungering for change and they showed that,” Mr. Johnson said. He waxed philosophical when asked about Mr. Crowley’s defeat. “In the political world, one day you’re up, the next day you’re down,” he said. “Politics is cyclical; life is cyclical.”

Mr. Crowley took over the perch 12 years ago from his mentor and predecessor in Congress, Thomas J. Manton, whom many credited with saving the local party after a corruption scandal under Mr. Manes in the mid-1980s. Mr. Crowley led the county party and, through an alliance with the Bronx Democratic leaders, gave officials from both counties a greater voice in citywide politics.

“The Queens machine was part of the coalition that put Ed Koch in office,” said Michael Krasner, a professor of political science at Queens College. “They were extremely influential in terms of nominations, elections and also in terms of land-use decisions.”