Chrys Kefalas, an openly gay Republican, announced Tuesday he is running for the seat Sen. Barbara Mikulski, D-Md., will vacate next year.

The 36-year-old candidate shared his intentions with Fox News' Greta Van Susteren, noting his work as speechwriter for former Attorney General Eric Holder and present employment as vice president for the National Association of Manufacturers. He said he was motivated to run after Md. Gov. Larry Hogan won last year's state election.

In November, Kefalas and local radio host Tommy McFly announced their engagement to the public after six months of keeping the secret, saying they did not want the news to interfere with his launching a Senate bid exploratory committee or his partner's on-air image.

Kefalas joins an already crowded GOP primary field with four other hopefuls. On the Democratic side, three current members of Congress — Reps. Donna Edwards and Chris Van Hollen — are fighting for the nomination.

A Baltimore Sun poll conducted last month indicated 59 percent of likely GOP voters were undecided on which candidate they would support, making Kefalas a contender in the race despite his late entrance.

The Senate seat is rated Safe Democrat by the Rothenberg and Gonzales Political Report.

"Customer service is what Marylanders expect from my family's restaurant. It's time we demand the same from our elected leaders," said Chrys Kefalas.