President-elect Donald Trump named University of Iowa alum Matthew Whitaker to be the U.S. ambassador to the North Atlantic Treaty Organization under his administration on Wednesday morning.   

Whitaker previously served as interim attorney general during Trump’s last presidency and was a vocal supporter of Trump during the Iowa caucuses, appearing at several campaign rallies.

The appointment comes as Trump is working to fill his cabinet before he takes office on Jan. 20.

Whitaker will be the chief diplomat to NATO. Trump criticized the organization often during his campaign, saying he believes European allies don’t pay their fair share. The organization was organized to defend Europe against Russia in 1949.

“Matt is a strong warrior and loyal Patriot, who will ensure the United States’ interests are advanced and defended,” Trump said in a statement Wednesday. “Matt will strengthen relationships with our NATO Allies, and stand firm in the face of threats to Peace and Stability – He will put AMERICA FIRST.”

Whitaker served as interim attorney general from November 2018 to February 2019, between the firing of Jeff Sessions and the hiring of William Barr. His previous appointment was contentious because he was not serving in a role confirmed by the Senate before he was named acting attorney general.

Whitaker was formerly the U.S. Attorney for the Southern District of Iowa and played football during his time at the UI, receiving a Big Ten Medal of Honor.