WASHINGTON (CNN) -- The man whose appointment as an interim U.S. attorney in Arkansas helped prompt the controversy regarding the firing of federal prosecutors has announced he will leave his job effective Friday.

In a press release Thursday announcing his resignation, Tim Griffin, 38, says he will be pursuing opportunities in the private sector.

"I greatly appreciate the opportunity to serve in the Department of Justice, especially as United States Attorney. I have particularly enjoyed serving in my home state of Arkansas and look forward to remaining here," Griffin said.

Griffin's predecessor, Bud Cummins, was one of the eight U.S. attorneys fired last year. Originally Justice Department officials, including the attorney general, cited performance reasons for Cummins' dismissal but later acknowledged he was moved out to make room for Griffin, who used to work for Deputy White House Chief of Staff Karl Rove.

E-mails released as part of the congressional investigation into the prosecutors' firings showed White House and Justice Department officials discussed for many months how to put Griffin into the position and whether in his case a controversial provision of the Patriot Act that allowed the attorney general to bypass the Senate to appoint U.S. attorneys should be used. In the end, that authority was not used. Instead Attorney General Alberto Gonzales used existing powers to name Griffin as interim U.S. Attorney last December.

-- CNN Senior Producer Kevin Bohn