After graduation from New York Law School, McGowan served as an Assistant District Attorney in The Bronx and a Senior Assistant District Attorney in his home county of Rockland.

[1] He was first elected to public office in 2019, as a member of the Rockland County Legislature from the 15th District.

[2][3] The 15th District included parts of Orangetown, Clarkstown, and Chestnut Ridge.

He won the election against Democratic challenger Eudson Francois and was sworn in on January 1, 2023.

In November 2024 he lost his reelection to longtime Democratic Rockland County legislator Aron Wieder by a margin of 7.5% points.