In 1908, Gillhaus was substituted for the original nominee, "Morrie" Preston, a miner who was arrested on murder charges during a citywide strike in Goldfield, Nevada, in 1907. Gillhaus and his running mate Donald L. Munro, of Virginia, received 14,029 votes.
In 1912, as the VP candidate on the ticket with Arthur E. Reimer, Gillhaus got 29,213 votes.
In 1914, he ran for New York State Engineer and Surveyor.
In 1916, he ran for U.S. Senator from New York.
In 1918 he ran for Lieutenant Governor of New York.
In 1920, he was the Socialist Labor Party VP candidate on the ticket with William Wesley Cox.
In 1930, he ran for New York State Attorney General.