 Hirsch was elected to the Senate for the 6th District (6th, 7th, 9th and 10th wards of the City of Milwaukee) in 1920, to succeed fellow Socialist W. C. Zumach (who was not a candidate for re-election).He served four years starting in 1921.He was elected unopposed, receiving all but three of the 8,828 votes cast; and was assigned to the standing committee on corporations.