Markethy McClellan was convicted Saturday on charges from a racially tinged brawl last summer in the city's Iron Island neighborhood, but co-defendant Angelo Kidd was acquitted.
McClellan, 17, was found guilty of second-degree assault and criminal possession of a weapon, fourth degree. Kidd, 17, was acquitted of all charges.
The two black teens were accused of stabbing three white men during a street brawl the night of July 22.
McClellan had testified during the two-week trial that he used his pocket knife to save his life after he, Kidd and three other African-American teens were attacked by about two dozen white men.
Frank Mietlicki, one of the stabbing victims, denied that he or his friends threatened the defendants but conceded they exchanged words and he and his friends "ran up" to the two and initiated the fight.
Prosecutor James Q. Auricchio questioned the defendants' self-defense claims, noting the wounds the three victims suffered could not have been inflicted by someone wielding a knife while lying on the ground, as McClellan had testified.
The jury, which deliberated for four days, considered first- and second-degree assault and weapons counts against both teens.
McClellan admitted in testimony that he was the only one carrying a knife during the brawl at Greene and Hennepin streets.
He faces a prison term of up to seven years on second-degree assault when he is sentenced June 19 by State Supreme Court Justice Russell P. Buscaglia.
Last week, Jacob Dabbe, 20, and Eric Dragone, 17, said McClellan stabbed them as they fought.
Mietlicki, 28, testified he was high on drugs when Kidd stabbed him in the chest. DNA evidence showed only McClellan stabbed the three, and prosecutors later conceded it was highly unlikely Kidd had a knife.
McClellan, who remains jailed facing sentencing for an unrelated robbery, offered the only testimony for the defense. Taking the stand Monday and Tuesday, he said Kidd and three friends were accosted by the three victims and about two dozen others.
McClellan said he and his friends were walking along Lovejoy Avenue from a friend's house to a store when they were accosted by the white men, who followed them and taunted them with racial epithets.
McClellan said he and his friends tried to evade the gang, which caught up with then. He said he carried the pocket knife for his part-time job at Quincy Street youth center.
He said he began swinging the knife "wildly" as he was kicked and punched because he feared for his life.
In another case linked to last summer's racial problems in that part of city, Erie County Judge Shirley Troutman Tuesday sentenced Sean M. Braven, 19, of Marion Street to 30 days in jail. He pleaded guilty to misdemeanor hate-crime of attempted assault on a black man July 16.
He was the fourth of five white defendants to be sentenced in the July 16 attack at Seneca and Babcock streets.