He enlisted in the Hospital Corps of the United States Army, and served three years during the Spanish–American War.
He served for two years as a deputy sheriff, and at the time of his election to the Assembly had been operating a school supply and confectionery store.
Masiakowski had never held any public office (except that in 1917 he was appointed by Mayor of Milwaukee Dan Hoan as commissioner of the Community Christmas Board) until elected to the Assembly in 1918 to succeed Democratic incumbent Thomas Szewczykowski (who did not run for re-election).
He received 1,239 votes to 1,086 for Republican Klemens Borucki and 1,020 for Democrat Frank Krempinski.
[1] He did not run for re-election in 1920, and was succeeded by fellow Socialist Stephen Stolowski.