He was born on 12 April 1877 to parents Leander D. and Etta M. Stinemates.
He was a Methodist and married Edith Conrad in 1900, with whom he had two children, Harold and Velma.
Stinemates was first elected a Montgomery County supervisor in 1931, and relinquished control of his farm to his son upon taking office.
After a nine-year tenure as a county supervisor, Stinemates won his first election to the Iowa House of Representatives in 1940, from District 12.
George Stinemates died in Red Oak on 28 April 1963.