After turning the Nets into a playoff team in their first season in Brooklyn, general manager Billy King is set to remain in charge of the franchise for the foreseeable future.

League sources confirmed to The Post that King, who oversaw the transformation of the franchise from a moribund lottery team in New Jersey to a 49-win team that finished fourth in the Eastern Conference this season but lost 79-76 to the Bulls in Game 3 of their first-round series last night, will soon be receiving a multi-year extension to remain atop the Nets’ front office.

His contract had been set to expire at the end of the season. Yahoo! Sports first reported the extension.

King was hired by the Nets in July 2010, on the heels of the team’s 12-70 campaign in its final season in the Meadowlands. He then spent the next two years trying to acquire assets to land stars in order to enter Brooklyn with a team ready to be a factor in the Eastern Conference.

He wound up finding the face of the franchise he was looking for in star point guard Deron Williams, whom he landed in a blockbuster trade with the Jazz a day after the Nuggets finally decided to send Carmelo Anthony to the Knicks in February 2011.

Then, after unsuccessfully spending much of the lockout-shortened 2011-12 season trying to trade for Dwight Howard, King then acquired Gerald Wallace at the trade deadline last March before leading the franchise into a dramatic roster overhaul last summer ahead of the team’s move to Brooklyn.

In addition to convincing Williams to re-sign, as well as re-signing Wallace and Brook Lopez — who was a restricted free agent — King also acquired Joe Johnson in a trade with the Hawks, pulled off a sign-and-trade deal for Reggie Evans and picked up C.J. Watson, moves that helped the Nets become a contender in the Eastern Conference this season.