When William B. Johnson was born in 1830, in Norfolk, Ontario, Canada, his father, Levi Johnson, was 29 and his mother, Margaret Backhouse, was 21. He married Mary B. Dubid on 7 May 1852, in Ontario, Canada. They were the parents of at least 1 son and 4 daughters. He died on 28 November 1904, in Brockway, St. Clair, Michigan, United States, at the age of 74.