US president Donald Trump's son-in-law, Jared Kushner, occasionally used his personal email account to communicate with colleagues in the White House, his lawyer said.
Between January and August, Mr Kushner sent or responded to fewer than 100 emails from White House officials from his private account, attorney Abbe Lowell said in a statement.
"These usually forwarded news articles or political commentary and most often occurred when someone initiated the exchange by sending an email to his personal, rather than his White House, address," Mr Lowell said.
The attorney said Mr Kushner, a key aide to Mr Trump, uses his White House address to discuss White House business and that any non-personal emails have been forwarded to his official account and preserved.
Politico first reported Mr Kushner's use of a private email account.
The use of personal email to discuss government business is a politically freighted issue that factored prominently in last year's presidential election.
Hillary Clinton faced an FBI investigation for much of her unsuccessful White House bid over her use of a private email server as secretary of state.
Former FBI director James Comey said that though Mrs Clinton and her aides were "extremely careless" in their handling of classified information, there was no evidence that anyone intended to break the law. He recommended against prosecution.
Mr Trump argued during the campaign that Mrs Clinton deserved to be prosecuted and has continued to suggest that even after being elected president.
At a political event in Alabama on Sunday, he responded to supporter chants of "lock her up" by saying, "You've got to speak to (Attorney General) Jeff Sessions about that."