President Donald Trump has named a replacement for Secretary of Defense James Mattis. Current Deputy Secretary of Defense Patrick Shanahan will replace Mattis.

Trump announced the move Sunday in a tweet. “Patrick has a long list of accomplishments while serving as Deputy, & previously Boeing,” the president said, “He will be great!” (RELATED: Mattis Retires From Trump Administration)

I am pleased to announce that our very talented Deputy Secretary of Defense, Patrick Shanahan, will assume the title of Acting Secretary of Defense starting January 1, 2019. Patrick has a long list of accomplishments while serving as Deputy, & previously Boeing. He will be great! — Donald J. Trump (@realDonaldTrump) December 23, 2018

Here are some career highlights for Shanahan, according to his bio on the Defense Department website:

Patrick M. Shanahan is a Washington state native.

Shanahan attended the University of Washington and graduated with a degree in mechanical engineering.

Shanahan has two advanced degrees from the Massachusetts Institute of Technology.

Shanahan worked for Boeing for over three decades.

Shanahan served as Boeing senior vice president, Supply Chain & Operations.

Shanahan also served as vice president and general manager of Boeing Missile Defense Systems and as vice president and general manager of Boeing Rotorcraft Systems.

Shanahan was appointed 33rd Deputy Secretary of Defense on July 19, 2017.

President Trump announced that Mattis was stepping down earlier in the week. Mattis served two years in the position with distinction, focusing on the fight with ISIS and combatting global terrorism.