Jonathan graduated from Deerfield Academy in 1956 and graduated from Colby College in 1960 with a BA degree. He was commissioned in the Navy and was active for 3 years. He remained in the Naval Reserve for a total of 22 years and retired as a commander. He joined Hornblower and Weeks in 1963 and remained with them for 11 years. He joined Cummings & Co. in 1974 and was with them through the merger with Brown, Lisle & Marshall, Inc. in December 1984, when he became a partner. He now enjoys the status as a partner emeritus.
Jonathan grew up on a small farm in Rehoboth, MA. He now resides in Providence, RI, and enjoys time with his three children and eight grandchildren.