Steward, 23, had been charged with second-degree murder, three counts of armed criminal action, first-degree assault, and unlawful use of a weapon.
He pleaded guilty on the murder, assault, and two armed criminal action charges along with unlawful use of a weapon and unlawful possession of a firearm.
Steward was sentenced to 18 years in prison as part of the plea agreement, the Jackson County Prosecutor’s Office said.
He received 15 years on the for one of the weapons and the murder charge, five years each for the two armed criminal action charges, and 10 years for the assault. The sentences will be served concurrently.
Steward received three years for the firearm possession charge, which will be served consecutively.
Lee's Summit Police Chief Travis Forbes thanks Jackson County Prosecuting Attorney Jean Peters Baker's office and the Kansas City, Missouri, Police Department for the time and resources put into bringing Orr's killer to justice.
Orr, 30, was not the intended victim in the shooting, which happened near Californos. He was an innocent bystander.
"Obviously, there is no amount of justice that will account for the life that a man like Thomas Orr lived," Forbes said in a statement from LSPD. "His contributions to our community will never be forgotten. Like many victims of this senseless type of crime, we wish we could have him back."
According to police, Steward was arguing with a woman, who was shot in the arm during the incident, and exchanged gunfire with Jeremiah Crow at the crowded Westport bar before fleeing the scene in a Dodge Charger, court records said.
Crow was charged separately with third-degree assault. It has been amended to first-degree assault and is scheduled for trial Nov. 13.
Orr had worked as a school resource officer at Bernard Campbell Middle School in the Lee’s Summit Police Department for more than two years when he was killed.
"My thoughts today are with Thomas's family, our community, and our family at LSPD," Forbes said. "Rest in peace, Thomas."
Steward originally pleaded not guilty in September 2017.