At the age of 26, Kennedy decided to leave Ireland, largely because he knew that a third-born son had virtually no hope of running his family's farm. His good friend at Cherry Bros. Brewery in New Ross, Patrick Barron, who taught Kennedy the skills of coopering, had come to that conclusion months earlier and left for America. In October 1848, Patrick Kennedy decided to follow. Patrick Kennedy arrived in Boston on April 22, 1849, having sailed from Liverpool, England on the Washington Irving, a substantial packet ship from the East Boston yard of Donald McKay. Patrick Barron helped settle him into Boston life and organized his coopering job on Noddle's Island (present-day East Boston). Not long after, Barron's cousin Bridget Murphy (1821-1888), who was the daughter of Phillip Murphy (1771-1850) and Mary Barron (1776-1846), made her way to Boston. She and Kennedy were married in the Holy Redeemer Church on September 26, 1849, by Father John Williams, who later became Boston's Roman Catholic Archbishop.