Now, the latest addition to the team is drawing a different kind of attention.
Paul Manafort has been added to the Trump team as the campaign’s convention manager, showing that the real estate magnate-turned-reality star-turned politician is grappling with the inner workings of a possible contested convention.
Unlike much of Trump's relatively young staff that helped the Republican front-runner earn his early primary victories, Manafort is arguably more of an establishment figure.
Even though the Trump campaign's release only credits Manafort, 66, with experience spanning three decades, one of his biggest victories came four decades ago.
When asked whether he considers himself an establishment insider, Manafort was not ready to commit one way or another.
"Depends on who you talk to if I'm part of the establishment or part of the anti-establishment," he told CNN last week. "But the point is that I understand the establishment. I've run campaigns. That doesn't make you the establishment.
"Do I have relationships that go back into the system? Yes. Some of those relationships see me as a bridge to Trump now. They want to be for Trump. They didn't have a way in. They're now talking to me, finding a way in," he said.
In the Trump campaign's release announcing Manafort's hiring, he is described as “volunteering his considerable insight and expertise."
Close to Trump
The addition of Manafort to the team may have been in the works for some time. During an interview with CNN, Manafort said that he has known Trump "since the 1980s."
"We talked about it and he felt I could help him," Manafort said of his decision to come on board.
Those close to the campaign have confirmed that Manafort is working on a volunteer basis, which was noted in the initial release. What that means, they say, is that Manafort has no interest in the campaign's top job: campaign manager.
Lewandowski's lawyers have said he is "absolutely innocent," and he is expected to enter a not guilty plea. "He is completely confident that he will be exonerated," his lawyers said in a recent statement.
Indeed, the Trump campaign has reiterated that Manafort is working closely with both Lewandowski and deputy campaign manager Michael Glassner, despite reported friction between Manafort and Lewandowski, who have disagreed in a couple of meetings as they begin their new working relationship, according to sources close to the campaign.
"Paul is a great asset and an important addition as we consolidate the tremendous support we have received in the primaries and caucuses, garnering millions more votes than any other candidate," Trump said in the March 29 release announcing the addition of Manafort.
ABC News' John Santucci contributed to this report.