Fish graduated with Bachelor of Laws in June 1903 and promoted to Captain in the 1st Wisconsin Infantry Regiment. He was admitted to the State Bar of Wisconsin in 1903 and began practice law in Racine and then Madison, Wisconsin. In 1907, Fish moved to Milwaukee and began working for a law firm Quarles, Spence &amp; Quarles. He rose to the rank of Major in the National Guard by February 1913 and when his regiment was called up for federal service in July 1916, he served on the Mexican Border during Pancho Villa Expedition.