According to the USA Military Medals website, the Navy Good Conduct Medal is awarded to each member of naval personnel who completes three years of honorable service. The medal can be awarded by a commanding officer.
The U.S. Navy website explains the Navy Good Conduct Medal dates back to the U.S. Civil War. Naval history dates the first issue of the medal in 1865, making it the third oldest continuously awarded medal in the U.S. military.
During periods of war, the Navy Good Conduct Medal can be awarded to naval personnel completing one year of honorable service. The Grunts Military website explains that in 1996, the eligibility requirement for the award was reduced from four years of service to three.
The Grunts Military website explains that in order for the medal to be awarded, naval personnel must have a clean record, without court martial or civil convictions. Each member of naval personnel eligible for the medal must also maintain performance marks for their duties that are above 2.0.