After years of military structure, the beloved marine James Mattis had a wedding no one would have expected.

After more than four decades of being married to the U.S. Marine Corps, retired Gen. James N. Mattis went for a new bride during a Las Vegas wedding ceremony officiated by an Elvis impersonator.

The legendary Marine and former Trump administration defense secretary, known affectionately in the Corps as the “Warrior Monk,” exchanged wedding vows on Saturday with Christina Lomasney, a physicist and tech entrepreneur who works at the Pacific Northwest National Laboratory in Richland, Washington.

Politico, which reported the surprise nuptials, said the couple met at a bar. According to media reports, they were earlier married by a priest on the banks of the Columbia River.

Brian Mills, the Elvis impersonator who performed the ceremony, was in a photograph published by Politico standing next to the beaming newlyweds.

Mr. Mills said Las Vegas is expected to host 80,000 weddings in 2022. 

“Many of them aren’t Marines,” he wrote in a Twitter message. Mr. Mattis was “one of the happiest [grooms] I’ve had in 20 years, though.”

Mr. Mattis is a native of Richland, Washington, who enlisted in the U.S. Marine Corps Reserve at the age of 18. He served 44 years in the military, commanding at all levels and was Mr. Trump’s first secretary of defense before breaking with the president over Syria policy and resigning in January 2019.

Ms. Lomasney was a former project manager at Boeing and later founded Modumental, a Seattle startup company that markets a new steel manufacturing process.