Grosso is the 2012 cycle’s first at-large challenger. (DAVID P. GROSSO)

We have our first official challenger for an at-large seat on the D.C. Council: David P. Grosso, a former high-ranking aide to Del. Eleanor Holmes Norton (D-D.C.), declared his candidacy with election authorities today.

Grosso is running as an independent, which thanks to the District’s set-aside of two at-large seats for non-Democrats, essentially means he’ll be taking on one-term incumbent Michael A. Brown (I).

Grosso declined to comment ahead of his campaign kickoff, scheduled for 4 p.m. Friday Saturday at Colonel Brooks’ Tavern in his home neighborhood of Brookland.

But his old boss and new campaign chairman, former council member Sharon Ambrose (D-Ward 6), has plenty of nice things to say about Grosso, who headed her economic development committee staff.

“He is very bright, very committed, hardworking and he knows the city well,” she said.

As her committee clerk, Ambrose said that Grosso shepherded numerous development projects, including the financing of what is now Nationals Park.

Grosso (pronounced GRAH-so) left his post as Norton’s chief counsel in 2008 to serve as vice president for public policy as CareFirst BlueCross BlueShield, the region’s largest health insurer, where he’s working on implementing the federal health-care reform law.

“He’s not looking for as job; he’s got a good job,” Ambrose said. “I think that David represents a new breed of Washingtonians. He comes at it from the best possible direction. He’s kind of an outside insider, if you will.”

UPDATE, 4:35 P.M.: Grosso’s kickoff is Saturday, not Friday.