Former congressman and Staten Island Borough President Guy Molinari, a power broker who helped launch the political career of former Mayor Rudy Giuliani, died Monday. He was 89.

Mr. Molinari, a Republican, was a lawyer and fought in the Korean War as a Marine. He represented Staten Island in the state assembly and later in Congress before he was elected borough president in 1990, a role he held until 2001.

As...