William Carson, 24, faces two counts of first-degree reckless injury and five counts of first-degree recklessly endangering safety, all felonies.
Several children were playing in the snow on Jan. 4 when they began lobbing snowballs at passing cars, prosecutors said. The driver of one vehicle that was struck got out and began firing a handgun as the kids ran away.
A 13-year-old boy and 12-year-old girl were hit in the thigh and forearm, authorities said. A third child was grazed by a bullet.
Investigators found nine spent shell casings from a 9 mm gun at the scene, along with two fired brass bullet rounds.
Carson was arrested by Oak Creek police on Jan. 12 after he fled from officers and was found to allegedly driving under the influence. The gun used in the shooting was found in the glove compartment of his vehicle and test-fired by investigators.
Carson told authorities he purchased the weapon for self-defense 11 days before the shooting, Fox News affiliate WITI-TV reported.
He was ordered held Sunday on $35,000 bond. His next court date is scheduled on Feb.25.
The Associated Press contributed to this report.