Minkley was appointed as alderman-at-large in the city of Milwaukee by mayor Emil Seidel, to fill the vacancy created by the resignation of Victor L. Berger after Berger's 1910 election to Congress. Minkley was first elected a member of the Assembly in the Fourth district of Milwaukee County in 1912, with 2365 votes to 1969 for independent Paul G. Dorow, 1331 for Republican Max J. Leutermann, and 54 for Prohibitionist Peter J. Norgaaard, succeeding his fellow Socialist Max E. Binner Minkley served on the Assembly's Committee on Municipalities. In 1914 he was re-elected by a narrow margin, with 2295 votes to 2209 for Republican Walter F. Mayer. He was assigned to the Committee on the Judiciary for the 1915-1916 Assembly session. In May 1915, he requested an indefinite leave of absence, as the $500 salary and what money he had been able to earn as a housepainter while the Assembly was not in session was not sufficient to pay his expenses in Madison. While in the Assembly, he continued his work as Socialist Party state organizer. He was succeeded in the Assembly in the 1916 election by fellow Socialist Henry Ohl, Jr..
After the Assembly
After leaving the Assembly, Minkley continued as an activist. He frequently appeared before the legislature on behalf of Socialist legislation or on behalf of unions. As a lobbyist for the Brewery Workers Union, he wrote, published and distributed 2,500,000 copies of a pamphlet against Prohibition, and appeared before the United States Senate and five state legislatures in opposition to it. When the Milwaukee City Hall's Council Chambers were remodelled in 1931, Minkley contributed a stencil design for the ceiling and anteroom on the theme "Human Endeavor and Progress". This led to some complaints from the Milwaukee Art Commission, which condemned the designs as the product of "a painter, not an artist." In 1934 he was the Socialist nominee for the Fifth Wisconsin State Senate District, garnering 6,458 votes to 10,435 for Democrat Harold Schoenecker, 6,916 for Republican Bernhard Gettleman, and 5.674 for Progressive Gustave Dick. Minkley's rhetoric was often vigorous. During a 1935 rally in the Assembly chamber in favor of a bill to create a state corporation to operate shuttered factories and employ jobless workers, he told the Assembly that if the bill did not pass, its supporters would return at the next session with baseball bats "to drive you out." In 1937, Minkley was state secretary of the Socialist Party, and expressed the Party's concern that the Civilian Conservation Corps was "a breeding spot for militarism or Fascism."
Personal life
On September 29, 1934, he married Anna Hunter, a widow whom he'd met at the Wisconsin Socialist Party annual picnic in Pleasant Prairie. He already had six children by a prior marriage. He died July 26, 1937, of a stroke.
