LONDON — Leftfield Entertainment founder-CEO Brent Montgomery is to become the head of ITV Studios U.S. Group, the largest independent producer of unscripted programming in the U.S.

New York-based Leftfield was acquired last year by ITV for an eye-popping $360 million, a price tag that could rise depending on how the company performs during the next few years. Leftfield is home to History’s global hit “Pawn Stars” and many other cable reality series.

Montgomery’s ascent into the ITV U.S. top job has been in the works for some time although it was a complicated process to sort out how his earn-out on the 2014 acquisition would mesh with his CEO responsibilities to the larger group. ITV’s Leftfield acquisition was among the largest in a slew of acquisitions of production companies that ITV has made in the U.S., U.K. and Europe during the past four years.

ITV declined to comment.

It’s expected that Montgomery will be succeeded at Leftfield — which itself is a cluster of the production banners Leftfield Pictures, Sirens Media, Loud and Outpost Entertainment — by Leftfield president David George. He’s been with the company since 2010 and was upped to president of Leftfield Pictures last year.

Montgomery’s promotion fills the void left in January when Paul Buccieri left ITV Studios U.S. Group to join A+E Networks. ITV Studios U.S. Group includes ITV Studios America and also owns controlling stakes in Leftfield, Gurney Productions, Thinkfactory Media and High Noon Entertainment, among other companies. The group’s shows include series such as “Hell’s Kitchen,” “Duck Dynasty,” “Cake Boss,” “Hatfields & McCoys,” “Teen Wolf,” “Pawn Stars” and “Real Housewives of New Jersey.”

As well as “Pawn Stars,” Leftfield’s shows include History “Counting Cars” and Bravo’s “Real Housewives of New Jersey.” Montgomery is the executive producer on “American Restoration,” “Counting Cars” and “Cajun Pawn Stars” for History, “Health Inspectors” for FOOD, and the “Oddities” franchise for Science Channel. Previously, he served as executive producer on the series “Ball Boys” for ABC, “Bridal Bootcamp” for Vh1 and “Monster In-Laws” for A&E.

He got his start in local news before breaking into entertainment as a freelancer honing his reality chops producing on “The Bachelor,” “Blind Date” and “Wife Swap” and about 15 other series. In 2008 Leftfield produced its first series “The Principal’s Office” for TruTV.

Montgomery’s rise, long rumored in reality TV circles, was first reported Wednesday by the U.K. website C21.

Cynthia Littleton contributed to this report.