Nahom Tsegazab was facing two counts of second-degree murder, one count of attempted murder and 22 counts of aggravated assault in the shooting in the city's east end.
The shooting outside a public housing complex killed Shyanne Charles, 14, and Joshua Yasay, 23 — both of whom police say were innocent bystanders.
Police have said they believe an altercation at a barbecue attended by about 100 people that night set off the deadly violence between members of two rival gangs.
Three people have been charged in the shootings.
Two counts of first-degree murder were laid against Shaquan Mesquito, 18, also known as Bam Bam. Mesquito also faces 23 counts of aggravated assault for wounding more than 20 people at the crowded outdoor party, including attempted murder of Tsegazab.
A 17-year-old male has also been charged with two counts of second-degree murder in connection with the shootings.