John was a successful merchant in Nova Scotia, carrying on part of the family business started by his father and uncle. He was a member of the 13th General Assembly of Nova Scotia for Shelburne, which ran from 1826-1830. He was expelled from the assembly during that session for making allegations about a fellow member and refusing to retract them. His battle with the legislature was carried out to a great degree in the press making him a popular hero and a well known Nova Scotian. A subsequent stand with the Tories during the “Brandy Dispute” of 1830 made him unpopular enough to make his future attempts at re-election unsuccessful. On April 30, 1835 he married Eliza Ann Mercein, from this marriage there were two issues, a son, Alexander Barry and Mary Mercein Barry. John Alexander Barry was fascinated by different area Indians, which is believed he traded with early in his merchant career, he became popular by his lectures, principally to Halifax audiences, on the customs, artifacts, and chiefs of the Micmac and other North American Indians. His greatest notoriety came by way of an unprecedented divorce suit brought by Eliza Ann Mercein Barry in the 1840s for the custody of her daughter since the court would not have committed her son to her under the law, however she won custody.(Rose, John Carter,Jurisdiction and Procedure in Federal Courts, United States - 1922' - Civil procedure) It is thought that living in Nova Scotia trying to raise four daughters by John's first marriage as well as her own two away from her parents in New York and in light of John's indifference to his family took her daughter and returned to New York. Eliza's father was a Methodist Minister in New York. His son, died in early adulthood in Oregon City, Oregon. His daughter, Mary Mercien Barry, married Joseph Ferry Andrews, their son Roger Fuller Mercein Andrews was the chairman of the Mackinac State Park Commission and the Mackinac Island News during the 1940s. In the 1930s he was publisher of the Detroit Times as well as Director-General of Hearst Detroit publications.