After completing nuclear power school , nuclear prototype, and submarine school, he reported to USS Thomas A. Edison (SSBN610). There he served as Electrical Officer, Interior Communications Officer, Damage Control Assistant, Chemistry/Radiological Controls Assistant and Main Propulsion Assistant through three Polaris deterrent patrols and a refueling overhaul.
He subsequently completed a tour of duty as Radiological Controls Officer at the Naval Submarine Base, Pearl Harbor. After completing the Submarine Officer Advanced Course, he served as Navigator/Operations Officer on USS Greenling (SSN614) through two deployments to the Mediterranean Sea and a "UNITAS" deployment to South America. In 1982, he was assigned as Executive Officer of USS Patrick Henry (SSN599), and operated the boat in the Pacific until its decommissioning in 1984.
In February 1985, Captain Gradisnik assumed command of USS Plunger (SSN595). During his three-year tour of duty, the USS Plunger completed two deployments to the Western Pacific and earned the Submarine Squadron 3 Battle Efficiency "E", a Meritorious Unit Commendation, and the Pacific Fleet Marjorie Sterrett Battleship Fund Award.
After a brief period as Submarine Squadron 3 Chief Staff Officer, Captain Gradisnik completed a joint service tour as the Navy Operations Branch Head for Commander in Chief, U.S. Pacific Command. He then attended the National War College at Fort McNair in Washington D.C., graduating in June 1992.
Following a six-month period as Submarine Squadron 17 Deputy Commander for Training and Operations, Captain Gradisnik reported to the Supervisor of Shipbuilding at Electric Boat in Groton, Connecticut to command the USS Maine (SSBN741). Upon commissioning, Captain Gradisnik assumed Command of the Blue Crew where he set records during the post-commissioning testing. His crew received the highest grades ever recorded for a newly commissioned submarine in the Operational Reactor Safeguards Examination (ORSE), Tactical Readiness Evaluation (TRE), Logistics Readiness Evaluation (LRE) and Mk 48/ADCAP Acceptance Inspection.
Captain Gradisnik is entitled to wear the Defense Meritorious Service Medal, Meritorious Service Medal with one gold star, Navy Commendation Medal, Navy Achievement Medal, Navy Expeditionary Medal, and National Defense Medal.