[citation needed] Following graduation from the Naval Academy, Tobin reported to USS Towers (DDG-9) where he served as First Lieutenant and Main Propulsion assistant.

In 1976, he reported to the Office of the Chief of Naval Operations and served in the Systems Analysis Division (OP-96) In 1979, he assumed command of USS Tattnall (DDG-19), where he completed two Indian Ocean and Persian Gulf deployments.

In 1981, he reported as Chief Engineer in USS Forrestal (CV-59), where he served for two years and participated in the 1981 Gulf of Sidra operations, two Mediterranean deployments and the initial phase of the Carrier Service Life Extension Program.

In June 1994, Rear Admiral Tobin assumed his duties as Vice Chief of Naval Education and Training.

After retiring from active duty in 1998, Rear Admiral Tobin became the Executive Director of the Educational Foundation of the Armed Forces Communications Electronics Association (AFCEA) in Fairfax, Virginia.

In 2002, after his retirement, Admiral Tobin reviewed A. Jay Cristol's book, The Liberty Incident: The 1967 Israeli Attack on the U.S. Spy Ship, for the US Naval Institute journal Proceedings.