Department of Veterans Affairs Secretary David Shulkin was appointed the designated survivor, per an administration official.
The designated survivor goes to a distant, secure and undisclosed location outside of Washington while everyone else gathers to listen to the President's address in the Capitol.
The designated survivor must be eligible to be president, and if a higher-ranking successor survives a potential incident, that person would become president ahead of the designated survivor. The practice started in the 1960s during the Cold War when there were fears of a nuclear attack.
The practice of a designated survivor recently spawned a television series on ABC. Actor Kiefer Sutherland plays a Department of Housing and Urban Development secretary who takes over the presidency following an explosion during the fictional State of the Union address.
Shulkin, Tuesday night's survivor, previously served as the VA's undersecretary for health and his nomination drew widespread praise across the aisle.
Trump did not have a full Cabinet to choose a designated survivor from, due to delays
in the confirmation process in Congress. He lamented the pace of his Cabinet confirmations during a news conference earlier this month.
"I think we're setting a record or close to a record in the time of approval of a Cabinet," Trump said. "I mean, the numbers are crazy. When I'm looking, some of them had them approved immediately ... That's all they're doing, is delaying."
Labor Department nominee Andrew Puzder, director of National Intelligence nominee Dan Coats, Energy Department nominee Rick Perry, HUD nominee Ben Carson, Interior Department nominee Ryan Zinke, Agriculture Department nominee Sonny Perdue, and US Trade Representative nominee Robert Lighthizer still have yet to be confirmed by the Senate.
Commerce Secretary Wilbur Ross is the most recent addition to Trump's Cabinet, confirmed on Monday.