Before serving on the state legislature, Fahy was president of the Albany City Board of Education.

On September 13, 2012, there was a primary election in the Democratic Party[1] to replace the retiring incumbent Jack McEneny, who had been an assemblyman for 20 years.

Fahy received 5,335 votes (36.34%) in a crowded field that included Frank J. Commisso, Jr., Christopher T. Higgins, William J. McCarthy, Jr., Jim Coyne and Margarita Perez, as well as write-in candidates.

[2] Ted J. Danz, Jr., however, beat Fahy in the Independence Party primary held the same date, 51 to 46%, with some write-ins.

[7] In February 2017, Fahy, along with Albany mayor Kathy Sheehan and congressman Paul Tonko, were criticized by Bishop Edward Scharfenberger for being Catholic politicians who supported and attended a rally for Planned Parenthood.