Schultz will remain with the campaign and "turn his focus to organizational planning for the general election and continuing to bolster the campaign's external outreach," according to a Biden campaign statement.
While the timing of the news was a surprise to allies of the campaign, the replacement of Schultz wasn't. The campaign had been beset with operational problems in the early stages, from poor fundraising to ground-game stumbles that led to big defeats in the first three early states.
Some within the campaign questioned the pressure to blame Biden's string of poor early state showings on the campaign manager instead of the candidate, whose lackluster debate performances and speeches haunted him in New Hampshire and Iowa, the first two early states where retail politics is a must.
Complicating Schultz's job, Biden was less inclined to listen to him than his chief adviser, Anita Dunn. Dunn took over some of the campaign's operations from Schultz before the New Hampshire primary and is now set to return as Biden's senior adviser.
O'Malley Dillon served in an advisory capacity during the Feb. 20 Nevada caucuses.
"I'm not going anywhere," Schultz told POLITICO on the day before the caucuses, when asked about rumors O'Malley Dillon would replace him. "I don't know where these rumors are coming from."
Prior to the Biden campaign, Schultz headed up Barack Obama's campaign in the crucial swing state of Ohio, which the president won twice. His counterpart in Florida, Steve Schale, is now the head of the Unite The Country super PAC, and has long expressed reservations about the behind-the-scenes efforts to unseat Schultz.
Schale recalls how Schultz in 2018 had discussed a potential Biden bid and said that Biden would win the nomination if he made it to South Carolina's Feb. 29primary, where black voters would elevate his candidacy - a prediction that came true.
"A lot of these people who have it out for Greg have no idea what they're talking about," Schale said.
Before Biden could even take the stage on South Carolina's primary night, talk again circulated that Schultz had to go - especially after House Majority Whip James Clyburn, whose endorsement in South Carolina helped propel Biden, criticized the campaign.
But the campaign again beat back the rumors as unfounded, and Clyburn walked back his remarks.