President-elect Donald Trump has endorsed Anthony Constantino, CEO of Sticker Mule, to fill the congressional seat that will be vacated by Rep. Elise Stefanik when she becomes U.S. Ambassador to the United Nations.

Constantino, who leads the Amsterdam, New York-based custom printing company, gained attention for his public disputes with local officials over a 100-foot pro-Trump sign. The endorsement appears to go against the preferences of the New York state Republican Party establishment.

Stefanik, who represents New York's 21st congressional district in the North Country region, was nominated by Trump to serve as U.N. Ambassador. Her departure will trigger a special election to fill the remainder of her term.

Constantino has been a vocal Trump supporter and his company has been involved in political merchandise. His previous conflicts with local authorities over campaign signage brought him into the public spotlight in the district.

The 21st congressional district covers a large swath of upstate New York, including the Adirondack region and areas along the Canadian border. The district has been considered a Republican stronghold in recent election cycles.