Francisco Alejandro Mendez, 18, faces seven felony counts, including murder in the first degree. He was also charged with premeditation, attempted murder in the first degree and five counts of aggravated robbery, according to the Shawnee County (Kansas) District Attorney's office.
Police connected the crimes to two related aggravated robberies that occurred on April 27 and 30.
Simmons and Ballentine were shot as they walked home from a party in Topeka, Kansas, just hours after the Giants selected Ballentine in the sixth round of the NFL draft. Simmons was pronounced dead 11 minutes after the 911 call to report the shooting.
Ballentine, 23, was shot in the backside and spent several days in the hospital. After being discharged, he remained in Kansas to attend Simmons' funeral while his fellow rookies reported for rookie minicamp.
Ballentine reported several days later and returned to practice later in the spring.
Mendez is being held on $1 million bond.