Striker Johnny Kenny will play on loan for the 2023 League of Ireland season.
After scoring 11 goals in his debut campaign for Sligo Rovers, Kenny moved to the Scottish champions a year ago and featured in their 'B' side.
A loan spell at Queen's Park in the Scottish Championship did not produce any goals in 12 appearances with Celtic willing to send Kenny back to his home country in a bid to find form again.
Several sides were chasing the 19-year-old, including his hometown club Sligo, but Stephen Bradley's men have secured his signature.