Florida Gov. Ron DeSantis on Thursday named Ashley Moody, the Republican attorney general, to succeed Marco Rubio in the U.S. Senate, elevating a close ally to Mr. Rubio’s seat after serving as secretary to President-elect Donald J. Trump was confirmed state.

“I wanted someone who had a proven track record of delivering results,” Mr. DeSantis said in Orlando before announcing Ms. Moody as Mr. Rubio’s successor. The announcement came a day after Mr. Rubio’s confirmation hearing before the Senate Foreign Relations Committee went smoothly. He is expected to easily win confirmation in a vote by the full Senate.

Ms. Moody, like Mr. DeSantis, was elected to statewide office in 2018 and re-elected in 2022. She was considered a leading candidate for Mr. Rubio’s seat and appeared alongside Mr. DeSantis at recent public events. She and the governor supported the new Trump administration’s hard line on immigration policy.

Ms. Moody, 49, is a fifth-generation Florida native. Before being elected attorney general, she was a district judge in Hillsborough County, home of Tampa. She previously worked as a federal prosecutor. Ms. Moody and her husband, a police officer, have two sons.

Although several Florida congressmen were interested in replacing Mr. Rubio, Mr. DeSantis made clear earlier this week that he was not inclined to choose any of them, fearing that House Republicans would have too small a majority in that chamber.

After Mr. Trump selected Mr. Rubio as his secretary of state in November, Republicans nominated Lara Trump, the new president’s daughter-in-law who had served as chairwoman of the Republican National Committee, for the Florida Senate seat. But Mr. DeSantis disagreed with the idea and Ms. Trump withdrew from consideration last month.

Ms. Moody would serve in the Senate until an election in 2026. Mr. DeSantis will also be term-limited this year. Ms. Moody was considered one of many Florida Republicans who might be interested in running for governor.