During his tenure, the media-savvy congressman launched high-profile and frequently controversial investigations into the Obama administration and other Democratic targets, notably Hillary Clinton's use of a private email server as secretary of state. Comey had reportedly indicated in a series of memos that Trump asked him to scale back his investigation into former national security adviser Michael Flynn.
Chaffetz immediately tweeted that he wanted to see the memo when news broke Tuesday.
Rep. Jason Chaffetz announced Thursday he'll resign from his seat in Congress on June 30.
Chaffetz, in a letter to Utah Gov. Gary Herbert, said he will step down effective June 30.
"The candidates have to make quick decisions, obviously, with the short timeline here", said LaVarr Webb, who publishes UtahPolicy.com and writes a column for the Deseret News.
House Freedom Caucus Chairman Mark Meadows, who sits on the oversight committee, said he had not spoken to Chaffetz directly, but was aware of his discussions with others about plans to step down from Congress.
In his first substantive comments about the appointment of a special counsel to probe Russian interference in the 2016 US elections, President Donald Trump denied that his campaign had been involved in any collusion with Moscow, as he declared that the probe "divides the country".
Herbert, whose chief of staff was at one time Chaffetz' chief of staff, said he hadn't talked directly with the congressman.
The U.S. Constitution and Utah law say that if a U.S. House seat becomes vacant, the governor will call a special election.
He told reporters Thursday from his home in a southern Salt Lake City suburb that he still has not seen the Comey memo or spoken with the former Federal Bureau of Investigation director.
When President Trump fired FBI Director James Comey, many expected - or hoped - that former prosecutor Rep. Trey Gowdy (R-SC) might be selected to take his place. Mr. Chaffetz's departure casts uncertainty into what is next for the committee's investigations.
Jacob Carlson, a 27-year-old college student in Chaffetz's district who has voted for Republicans and Democrats but leans Republican, said he viewed Chaffetz as a decent politician but was disappointed he did not investigate Trump more vigorously.
"Serving you in the U.S. House of Representatives for almost nine years has been a rare honor and privilege", he said.
"I think I'll actually miss the chaos; I kind of thrive in that", he said. "The overwhelming driving force is the idea that I just love my family".
The committee is also looking into whether Mr. Flynn may have violated the law by failing to obtain required permission from the U.S. Army and U.S. State Department before receiving money from entities associated with the Russian and Turkish governments.
"A lot of people will never believe that", he said.