"Today, I'm proud to announce that conservative businesswoman and political outsider Kelly Loeffler with be Georgia's next U.S. senator," Kemp said.
Kemp announced the decision Wednesday with Loeffler by his side.
"I know I have a lot of work to do to earn the trust and support of my fellow Georgians," Loeffler said.
President Trump had reportedly asked Kemp to appoint Rep. Doug Collins instead. But Senate Majority Leader Mitch McConnell expressed his support for Loeffler earlier this week.
"Everything I've heard about her, I think she's going to be terrific," McConnell said.
Loeffler, who's largely a political novice, will officially join the Senate on Jan. 1. She said Wednesday she intends to run in November's election to keep her seat.
Additional reporting from Newsy affiliate CNN.