In New England, he assumed various roles including serving as a consultant to printers, a Baptist minister, an owner of a limestone quarry, and a political figure elected as president of the combined towns of Providence and Warwick in colonial Rhode Island.

In October 1642, while Gregory was serving in the military, his wife, Abigail Dexter (née Fullerton), was apprehended by the House of Lords for printing prohibited literature and for refusing to disclose the names of the authors.

In 1644, they anonymously (but identified by the Dexters' damaged type) released several works by Roger Williams on religious toleration including Mr. Cotton's Letter Lately Printed and Queries of Highest Consideration.

Williams's book The Bloudy Tenent is sometimes attributed to the Dexters, but a typeface analysis points to the printers Thomas Paine and Matthew Simmons.

Dexter made annual visits to support Green and requested only a copy of the almanac in exchange for his services.

[17][14][18] Subsequently, Dexter turned his focus towards religion and became a pastor at the First Baptist Church in Providence, where he remained from 1654 until his passing in 1700.

He is an intelligent man, a master printer of London and conscionable (though a Baptist), therefore maligned and traduced by William Harris (a doleful generalist).

[27][28] Dexter died in 1700 and was buried on his home lot near the present day intersection of Benefit and North Main Streets.

[30][1][31][32] Although the younger Gregory Dexter's baptismal record has not been found, historian Bradford Swan argues that it can be safely assumed he was born in Old, rather than in Olney, Buckinghamshire, as some older genealogies suggest.