Born Michael Sinnott in Richmond Ste-Bibiane Parish, Quebec, he was the son of Irish Catholic John Sinnott and Catherine Foy. His parents married 1879 in Tingwick, Québec and moved the same year to Richmond, where John Sinnott was hired as a laborer. By 1883, when Michael's brother George was born, John Sinnott was working in Richmond as an innkeeper, a position he held for many years. His parents had all their children and raised their family in Richmond, then a small Eastern Townships village. At that time, Michael's grandparents were living in Danville, Québec. Michael Sinnott moved to Connecticut when he was 17 years old.