The 51-year-old constable was last month convicted by magistrates of common assault following a complaint by the boy's family.
Roger Hateley, from Tile Cross, Birmingham, had an unblemished 27-year record before the incident, which happened at a school while he was investigating a burglary.
A West Midlands Police spokesman said yesterday: "Pc Roger Hateley appeared before the Chief Constable, Edward Crew, this morning at a disciplinary hearing on a charge of criminal conduct. Three options were available to the Chief Constable - dismissal, requiring Pc Hateley to resign, or reprimanding him. After hearing all the facts and background, Pc Hateley was reprimanded.
"He will return to his duties as a scenes of crime officer."
Pc Hateley was suspended from the West Midlands force after he slapped a boy at a school last March. The child had repeatedly called the officer a "slaphead" and made grunting noises at the school gates.
Pc Hateley told Wolverhampton magistrates' court that he tried to grab the boy, who cannot be named for legal reasons, but made contact with his neck and jaw, causing reddening.
The former Parachute Regiment soldier and Venture Scout leader was devastated following his conviction for common assault.
He was fined pounds 250, and ordered to pay pounds 400 costs and to pay the boy pounds 30 in compensation. He received massive public support for his predicament including a campaign run by his local newspaper.Reuse content