President Trump is removing Billy Long from his job leading the Internal Revenue Service just two months after he was confirmed as commissioner, according to four people familiar with the matter.

Mr. Long, a former Republican congressman and staunch ally of Mr. Trump, is expected to be nominated to an ambassadorship, the people said. It is unclear who will next lead the I.R.S., which has had six different people in charge this year. Treasury Secretary Scott Bessent will serve as acting commissioner until a permanent replacement is in place, a senior administration official said.

Mr. Long had been an unusual choice to lead the I.R.S. He did not have much background in tax policy beyond promoting a tax credit that the I.R.S. has warned was riddled with fraud, and while he was in Congress he supported legislation calling for the abolition of the agency entirely.

Over his short tenure at the tax agency, Mr. Long, a former auctioneer, traveled to meet with I.R.S. staff across the country and appeared at a National Auction Association conference. He placed two top I.R.S. officials on administrative leave, amplifying a post on social media about the need to “purge” the agency’s work force.

At the same time, he has also repeatedly sent emails to all I.R.S. employees allowing them to leave work early on Friday afternoon.

“Please enjoy a 70-minute early exit tomorrow. That way you’ll be rested for my 70th birthday on Monday!” Mr. Long wrote to staff on Thursday.

The Trump administration has pushed to dramatically reduce the number of staff who work at the I.R.S., while at the same time seeking to use it to help deport migrants and scrutinize the tax-exempt status of universities.

Mr. Long did not respond to a request for comment. The I.R.S. did not immediately respond to a request for comment.

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