Senate Republican leader Mitch McConnell praised Mr McGahn as "the most impressive White House Counsel during my time in Washington".
McGahn was also among the White House officials who sounded an alarm when Sessions contemplated resigning as attorney general early in the administration.
"Iowa GOP Sen. Charles Grassley, chairman of the Senate Judiciary Committee, tweeted after the president's announcement: "I hope it's not true McGahn is leaving White House Counsel". Flood represented former President Bill Clinton during his impeachment and was hired by the Trump White House to deal with the Russian Federation investigation.
He was not aware that Trump planned to send the tweet before it posted, according to a person close to McGahn.
McGahn signaled his intentions to leave in March, but the retirement of Supreme Court Justice Anthony Kennedy delayed his departure from the White House.
China slams 'irresponsible' Trump accusations over North Korea
Tokyo is also pushing hard to resolve the sensitive issue of Japanese abducted by North Korea . South Korean Foreign Minister Kang Kyung-wha spoke to Pompeo by telephone Saturday.
Mr Trump made the announcement on Twitter, ending widespread speculation about Mr McGahn, who will be the latest in a long list of high-ranking advisers to leave Mr Trump's side. Recently, McGahn drew media attention after it was revealed he had met with special counsel Robert Mueller.
Axios' report cites anonymous sources three times. "He's super well-respected around the building but there's not a plan locked in place at this point".
If Trump worked with McGahn to fashion a pretext for firing then-FBI Director James Comey, Schiff said, McGahn would know whether it was over the Russian Federation probe.
McGahn has served an important role in the Trump administration due to his leadership on the nomination and confirmation of federal judges, including Supreme Court Justice Neil Gorsuch's confirmation.
"Don's significance to the judiciary, the White House and the nation can not be overstated, and I look forward to his continued efforts on behalf of our country", McConnell added.
PH pays tribute to US Sen. John McCain
Congressmen from 1983-1987, representing Arizona's first district, and was a Senator from Arizona from 1987 until his death. It sprang from his belief in democracy and freedom". "His significance went well beyond his own country".
After the news of McGahn's conversations with Mueller went public, Trump tweeted that McGahn was not a "RAT" like John Dean in the Watergate scandal.
"It is no surprise to read that he has gained the president's confidence already", Coffin said.
The Washington Post said in his interviews with Mr Mueller's team, which also is investigating potential obstruction of justice regarding the Russian meddling, Mr McGahn was asked about Mr Trump's actions in firing Federal Bureau of Investigation director James Comey in 2017. His reaction was, "Of course it happened this way", one person said.
Before working at the White House, McGahn was a campaign finance attorney at Jones Day, a Washington law firm that has filled several top legal roles within the Trump administration.
Australia PM Malcolm Turnbull clinging on amid fresh leadership challenge threat
Were she to win, she would become Australia's second female prime minister and the first from Western Australia since 1945. Labor has already released conflicting advice and leading constitutional lawyers have described the case as a grey area.