It is only the fourth time in 12 years that the department has given out the award, which is reserved for emergency incidents where firefighters show bravery and courage.
Fleming earned the medal for his actions June 5, when crews responded to a capsizing boat in Commencement Bay. They found one person on board was able to swim to shore and the other was clinging to a floatation device about 100 feet offshore.
While waiting for fire boat Destiny to arrive, Fleming volunteered to get into the 45 degree water to help the swimmer, who appeared to be having a hard time staying afloat.
He secured a tag line and swam to the man, then secured him to the tag line and kept his head above water until rescuers were able to pull them both to safety.