Manuel Concepcion Jr. was also convicted of weapons charges in the July 2011 attack on 45-year-old Ignacio Castro, who died about three weeks later from his wounds.
Atlantic County prosecutors say Concepcion stabbed Castro in the heart with scissors, but didn't say what spurred the brawl. The 34-year-old Atlantic City had denied delivering the fatal blow.
A witness testified that Concepcion left the scissors at the scene and asked him to dispose of them. Prosecutors said the witness tossed the scissors in an alley, but the handles broke off during the stabbing and were left behind.
Concepcion faces up to 30 years in prison when he's sentenced Nov. 21.