John Dowd, who joined the legal team in mid-June, is replacing Trump's longtime personal lawyer, Marc Kasowitz, as lead attorney representing the president, Dowd confirmed to ABC News.
The newest lawyer in the group, Ty Cobb, will take the lead in managing the team's external response to the Russia probe.
Mark Corallo, who was spokesman for Trump's legal team, resigned Thursday.
Dowd emphasized that even though he is moving into another role as the team's leader the group of lawyers serving as the president's outside counsel is a close-knit team. "We don't decide anything without talking to one another," Dowd said.
Kasowitz will remain on Trump's legal team and continue to represent Trump but in a lesser role, two sources with direct knowledge of the situation told ABC News Thursday night.
"Our task from the start was to stand up a team externally and internally to handle this for the president with our guidance, input, and assistance," a source in Kasowitz' law firm who has knowledge of the situation told ABC News.
"We got Sekulow to do the media appearances, Dowd to be the D.C. criminal lawyer, and Ty [Cobb] to handle the White House. And, most important, we got that team up and running with the president's confidence, which took a period or introduction and transition," the source said.
The source added, "Now we will let them do their jobs with our input and guidance to them and the president. Ty [Cobb] has the lead internally and given his very longstanding relationship with Dowd, will interact with him directly."
“I think that’s a violation,” Trump said in the interview. "This is about Russia!"
Trump did not explicitly say he would fire Mueller if such a situation arose, telling the Times that he "can’t answer that question because I don’t think it’s going to happen." But the president added that if Mueller did investigate, he would find that Trump's finances are "extremely good."
ABC News' Adam Kelsey and Justin Fishel contributed to this report.