After the war, Aplin returned to Michigan and engaged in mercantile pursuits at Wenona (later West Bay City and now part of Bay City). He was postmaster of West Bay City from November 1869 to June 1886. He served as township clerk and township treasurer, each for three years and was a delegate to the 1884 Republican National Convention at Chicago.[1]
Aplin was elected auditor general of the State in 1886 and 1888. He became interested in the construction of the electric railways of West Bay City and served as general manager until 1891. He was a member of the Michigan State House of Representatives in 1894 and 1895 and was again appointed postmaster of West Bay City, serving from October 1, 1898, to June 1902.