He was ordained at Exeter, Devonshire, England as a Deacon and a Priest on 29 July 1597. He spent his life's work as a Minister; first as a Curate to his uncle Radford Maverick at South Huish, Devonshire, England from 1606 to 1614 and then as a Rector at Beaworthy, Devonshire, from 1615 to 1629. Officially, he was instituted to St. Alban's Beaworthy,  Devonshire, England on 20 August 1615, at Silverton, Devonshire, England by William Cotton, Bishop of Exeter, on the death of John Norrice and on the presentation of Sir John Arscott. In March 1629, John Maverick resigned to emigrate to New England.

In 1930, John Maverick was chosen as one of the teachers of the Puritan church organized at Plymouth, England and was one of two ministers (along with John Warham) chosen to come over with the Mary & John.

John and family emigrated on the Mary & John, leaving Plymouth, Devonshire, England on 20 March 1630 and arriving in Nantasket, MA on 3 May 1630. The children who came over with John & Mary Maverick were Elias, aged 26; Mary, aged 21; Moses, aged 19; Abigail, aged 17; Antipas, aged 11 and John, Jr., aged 9 (The Mavericks took care of Roger Clap when he was a child).

In 1633 as one of a committee consisting of two ruling ministers and two deacons, Maverick helped to establish the rules of government for the town of Dorchester.

John Maverick served as a Minister of First Parish church until his death in 1935.