Marcus Bascus of East Orange was taken into custody in Wilkes-Barre, Pa., Wednesday.
He is charged with murder, conspiracy, attempted murder and weapons offenses.
Police say the 19-year-old Bascus provided a gun to 25-year-old Nicholas Welch after Welch was refused admittance to an off-campus Seton Hall party in East Orange.
They say Welch returned to the party and began shooting. Nineteen-year-old honors student Jessica Moore was killed and four people were injured.
Welch made his first court appearance Wednesday morning. Bail for both men has been set at $2 million.