Prior to the war John Bostwick was the High Constable for the District in 1800 then Deputy Sheriff in 1801. He was  also a surveyor and had surveyed several tracts along the Talbot Road and Lake Erie shoreline.

At the outbreak of the war John Bostwick was Capt in the 1st Regiment Norfolk Militia commanded by Major George Salmon. Fought at Detroit, Fort Erie, Frenchmens Creek and Malcolms Mills.  Wounded twice during the war. After the war he returned to his duties as Sheriff and remained in that position until 1819.  1820 he was elected to the Legislative Assembly but was defeated in the following elections.

1821 Was given an appointment as Commander of 3rd Regiment Middlesex Militia and was give a grant of land 1200 acres in what is now Port Stanley by Col. Thomas Talbot.