Chief Petty Officer Brian Bill was among 30 Americans and eight Afghans killed when a rocket-propelled grenade fired by a Taliban insurgent downed their helicopter last weekend.
Stamford firefighter Patrick Sasser and other classmates organized the vigil at Trinity Catholic High School.
It was held Saturday night at 7 p.m. to honor Bill and his service.
The Saturday event was open to the public and organizers expected hundreds of guests including members of Connecticut's congressional delegation.
Memorial services for the 31-year-old special forces fighter have been scheduled for Aug. 19 at St. Cecilia Parish in Stamford.