(CNN) -- President Donald Trump said Wednesday that Don McGahn will leave his job as White House counsel this fall following Supreme Court Justice nominee Brett Kavanaugh's confirmation.
The departure of a key member of Trump's legal team comes as special counsel Robert Mueller's investigation continues to consume much of the President's focus amid questions of potential obstruction of justice into the investigation of Russian interference in the 2016 election.
"White House Counsel Don McGahn will be leaving his position in the fall, shortly after the confirmation (hopefully) of Judge Brett Kavanaugh to the United States Supreme Court. I have worked with Don for a long time and truly appreciate his service!" Trump tweeted.
Sources close to the White House said earlier this month that McGahn was likely to leave his White House post after Kavanaugh is confirmed.
McGahn's standing in the White House has been the subject of much speculation following the disclosure earlier this month that he has cooperated extensively with Mueller's probe, participating in several interviews spanning 30 hours over the last nine months. The conversations have unnerved Trump, who didn't know the full extent of McGahn's discussions, two people familiar with his thinking have said.
Emmet Flood, who now directs the Russia legal strategy from inside the White House, is a potential replacement, CNN reported last week. McGahn fought to bring Flood onto the team and likes him very much, a source close to the White House said.
The news of McGahn's eventual departure comes amid the advancement of Kavanaugh's confirmation hearing, which is set to start in less than a week and last three or four days, according to Senate Judiciary Chairman Chuck Grassley.
Tumultuous tenure in White House
McGahn leaves his White House post after serving as White House counsel through the tumultuous first 18 months of Trump's presidency, steering the White House's handling of the Russia investigation and responding internally to the President's mercurial moods as the investigation ballooned.
His departure marks the latest of the handful of top aides who worked on the Trump campaign before joining the White House. McGahn served as the Trump campaign's top attorney throughout the GOP primary and 2016 presidential election, becoming a trusted adviser to the future president in the process.
He immediately faced controversy in his earliest days at the White House, beginning with acting Attorney General Sally Yates' warning to McGahn that then-national security adviser Michael Flynn could be blackmailed by Russia and that he had likely lied to Vice President Mike Pence. Flynn was forced to resign after reports revealed Yates' warning to McGahn about Flynn's conduct.
As the Justice Department and congressional investigations into Russian meddling in the 2016 election heated up, McGahn found himself increasingly at the center of Trump's and the White House's response to the investigation.
And when Attorney General Jeff Sessions faced pressure to recuse himself, Trump enlisted McGahn to urge Sessions not to take that step. Sessions eventually did recuse himself, giving his deputy, Rod Rosenstein, the ultimate authority to appoint a special counsel.
But for McGahn, the President's order to fire Mueller was a bridge too far -- with the White House counsel refusing to follow through on the order, a person familiar with the matter told CNN. The New York Times first reported Trump's move to fire Mueller and McGahn's refusal to carry out the order.
The slew of incidents involving the President and McGahn amid the Russia investigation made the White House counsel an important witness in Mueller's investigation.
Before joining the Trump campaign and the White House, McGahn worked at the powerful DC law firm Jones Day and previously served as a commissioner on the Federal Election Commission.