Coggeshall was very active in civil affairs, but a rift in the leadership of the colony caused him and several other leaders to leave in 1639, moving to the south end of the island and establishing the town of Newport. The towns of Portsmouth and Newport reunited in 1640 under the leadership of William Coddington, and Coggeshall was his assistant until 1647 when the two towns on Rhode Island united to form a common government with the towns of Providence and Warwick, and Coggeshall was elected President of the entire Colony of Rhode Island and Providence Plantations. His tenure was very short due to his death later the same year, but during his administration many laws were established which became the basis for the colony and the future State of Rhode Island.