John Stewart Miller was an Ontario farmer, merchant and political figure.
He was born in Camden Township, Addington County, Canada West in 1844, the son of Thomas Miller.
He studied at the Ontario Commercial College in Belleville.
He represented Addington in the Legislative Assembly of Ontario as a Conservative member from 1886 to 1890. Miller was a lieutenant in the local militia. In 1870, he started a cheese factory in Centreville with James North. Lapum.
In 1871, Miller married Carrie Hawley.
He was named clerk for Camden Township in 1875. In 1883, Miller became a merchant in Centreville, purchasing the business of A. North. Lapum.
He was county master for the Orange Lodge and master of the local Masonic lodge. He moved to Manitou, Manitoba in 1890 and returned to farming.
Miller served as reeve for Pembina, Manitoba from 1895 to 1897.