John's father was John Sayre, a sea captain, born in Philadelphia to British Loyalists who went to Canada in 1783. His mother was Eleanor Thompson who was born in England. The first child, this John, was born in England, the rest of his 6 siblings were born in Baltimore United States.
John was a carpenter/cabinetmaker. He married Harriet Wood in Virginia and in 1850 and 1860 they lived in Northumberland Virginia. They had 6 children: Theophilus, John, Columbus, Vener Randolph ('Vanarendo'?), Virginia N. and Emily E.