That was fast.

Rich Lazer, the Democrat who launched an unsuccessful bid for Congress this year, is returning to Mayor Kenney's administration.

The 33-year-old worked for Kenney almost his entire adult life, starting as an intern for the then-councilman and eventually becoming his deputy mayor of labor.

He resigned from that position in February to run for Congress. Lazer will go back to the post on May 29.

"Lazer has been a key adviser to the mayor on many issues, and he has certainly been missed during the past few months," said Mike Dunn, a spokesman for Kenney.

Dunn said Lazer had been "instrumental" in helping to reach agreement on a new labor contract with the city's blue-collar union as well as end the 2016 SEPTA strike.

Lazer is also an ally of John "Johnny Doc" Dougherty, the leader of the city's building trades, who is under federal scrutiny. Dougherty has denied any wrongdoing.

Dougherty launched a super PAC backing Lazer, which spent nearly $1 million on TV ads. Kenney appeared in the spots.

Dunn said that Lazer will work on "a number of pressing labor-related matters," including contract negotiations with the city's municipal white-collar union as well as the mayor's public works project, known as "Rebuild."

Lazer did not respond Friday to a request for comment.

Lazer campaigned to represent Pennsylvania's Fifth Congressional District, which is largely based in Delaware County but also includes parts of South Philadelphia and Montgomery County. He ran on a platform of Medicare-for-All and a $15 minimum wage, and received the endorsement of Sen. Bernie Sanders and several labor groups.

He came in third in the 10-person primary.