Jeffrey is the son of Calvin George Cook and Hazel Cadagan. His fabrication business grew out of his training as a machinist and iron worker. Susan Jean Gautier, his wife, graduated in Interior Design from Endicott College. Their children include two daughters and one son, all living in Massachusetts. Jeffrey was a participant in the DNA study of this family, linking him with Nova Scotia early-comer James Cook to Portaupique in the 1760s.

Children of Jeffrey Mark Cook and Susan Jean Gautier:

 

Melissa April Cook McNeilly

 

Tara Lynn Cook Haynes

 

Jeffrey Andrew Cook