Mallory, D.C. employment director since September 2011, will lead the city’s leading real-estate development trade group. (Courtesy of D.C. Department of Employment Services)

This post was updated at 12:45 p.m. with official confirmation and comment from Mallory

The District’s top employment official is leaving government for a private-sector post, leaving one of Mayor Vincent C. Gray’s top priorities in the hands of interim leadership as he embarks on a reelection campaign.

Lisa M. Mallory will become the new chief executive of the D.C. Building Industry Association, the Gray administration announced Friday. Mallory will leave her post as director of the Department of Employment Services in early January, and will be replaced by the agency’s chief information officer, Thomas Luparello, on an interim basis.

Mallory, in an interview Friday, said it was a “very personal decision” to depart government. “It’s a really exciting opportunity for me,” she said. “I have just had to insert balance in my life.”

Tackling unemployment was at the center of Gray’s 2010 election pitch, and he tapped Mallory, a longtime federal official who also served as a consultant and an executive at the Fannie Mae Foundation, to lead his efforts.

She launched Gray’s signature jobs effort, One City, One Hire, which aimed to match unemployed D.C. residents with available jobs through a rigorous pre-screening process and a series of targeted job fairs. The Gray administration credits One City, One Hire with placing more than 9,000 unemployed city residents in jobs, but it has been difficult to discern how many of those hires have been due to new efforts versus how many have been due to existing programs.

Mallory said the agency’s approach to getting unemployed residents into jobs has been transformed: “The big thing that’s different now is that we do a lot of work with the unemployed to prepare them for interviews, to get them in front of people who are hiring. We do a lot of pre-screening, pre-testing, and that is totally different.”

During her tenure, the District’s unemployment rate dropped from 10.1 percent to as low as 8.4 percent, though it has risen back to 8.9 percent in recent months — a phenomenon Gray has blamed on federal-sector cutbacks.

Mallory has also overseen the city’s Summer Youth Employment Program, which has generally run smoothly under her watch after several years under Mayor Adrian M. Fenty when the program, then serving more than 20,000 children, experienced significant management lapses.

At DCBIA, the city’s leading real-estate development trade group, Mallory will replace Gail Edwards, who is leaving the group after 41 years. Gray on Thursday attended a retirement celebration for Edwards and proclaimed it “Gail Edwards Day.”

Mallory will move to the opposite side of one sometimes fiery debate — over city “First Source” laws requiring the hiring of city residents on some city-subsidized construction projects. In her current role, Mallory has been charged with enforcing those requirements, often with subpar results; in her new role, she will be advocating for builders and developers who have called the requirements unfair and unworkable.

Mallory said she “developed a great relationship” with the development community while in her current post. “I’m very aware here about some of their concerns, and we have worked very hard to ensure that employers have a viable pool of candidates,” she said. “In the past there was not a very good pipeline that was not brought to the attention of the employers, and that has been addressed.”