File: Anthony Brown kicks off his campaign for his run for Maryland governor in 2014 after serving seven years as Lt. Governor. (Astrid Riecken/FOR THE WASHINGTON POST)

Maryland Gov. Martin O’Malley (D) on Saturday touted Lt. Gov. Anthony G. Brown (D) as his preferred successor, calling the newly announced gubernatorial candidate an “outstandingly effective” leader.

The event in Baltimore, at which the two shared the stage, was billed as O’Malley’s “official endorsement” of Brown’s 2014 candidacy for governor. O’Malley’s intentions have been clear for some time, but Saturday was the first time O’Malley has spoken out on Brown’s behalf since Brown kicked off his campaign Friday night in Largo.

“I’m telling you, friends, I’ve seen this guy work,” O’Malley said of Brown, whom he called “one of the most effective and substantive lieutenant governors in the United States of America.”

Brown, who also held solo events Saturday in Frederick and Silver Spring, is likely to face a competitive field of other candidates vying for the Democratic nomination in June 2014.

Both Attorney General Douglas F. Gansler (D) and Del. Heather R. Mizeur (D-Montgomery) are gearing up to run, and Rep. C.A. Dutch Ruppersberger (D-Md.), a former Baltimore County executive, is also looking at the race.

Howard County Executive Ken Ulman (D) has also been eyeing a run, but he has has been in talks with Brown about joining his ticket as the lieutenant governor candidate.

O’Malley, who has pushed same-sex marriage and several other controversial measures in recent years, received lukewarm approval ratings in a Washington Post poll in February.

But most analysts see O’Malley as an asset to Brown, a former delegate representing Prince George's County, because of his fundraising ability and his still-strong support among the Democratic base.

In the Post poll, 49 percent of Marylanders overall said they approve of O’Malley’s job performance, but 69 percent of registered Democrats voiced approval.

As O’Malley stood by his side Saturday, Brown ticked off a number of the administration’s accomplishments, including passage of a far-reaching gun-control bill and expansion of subsidized health care. He also said pushed his campaign theme of “making Maryland better for more Marylanders.”

The race could attract a half-dozen GOP candidates in a state where Democrats hold a 2-to-1 advantage in party registration and where only one GOP gubernatorial candidate — former governor Robert L. Ehrlich Jr. — has prevailed in the past generation.

Those looking at the race include Harford County Executive David R. Craig; Del. Ron George (R-Anne Arundel); Blaine R. Young, president of the Frederick County Board of Commissioners; Larry Hogan, a former Ehrlich Cabinet member who leads the group Change Maryland; Dan Bongino, a former Secret Service agent who ran unsuccessfully for the U.S. Senate last year; and Charles Lollar, a businessman who ran unsuccessfully for the House of Representatives in 2010.