Hawthorn signed the 19-year-old in September after he had an outstanding Gaelic Football season in Ireland. He gained a starting spot for Dublin in an All-Ireland semi-final at Croke Park in 2012 and was a highly rated prospect.
At the time, Kilkenny admitted the decision to leave Ireland and join Hawthorn was difficult but the lure of being a professional sportsperson and experiencing a different culture was too strong to pass up.
The Hawks have accepted Kilkenny's decision, with recruiting manager Graham Wright telling hawthornfc.com.au the club was disappointed but respected the reasons for the decision.
"We understand that ultimately the pull of home in Ireland, his family, friends, football and hurling was a significant factor in Ciarán's decision," Wright said.
Kilkenny said that while he enjoyed his experience and was grateful for the opportunity, it would be unfair for him to continue at the club at this time.
"I have always given my absolute commitment to any team in which I was involved and I feel it would be unfair on both Hawthorn and myself to continue in a situation where I am not 100 per cent committed and happy in myself," KIlkenny said.
Kilkenny outlined what drove his decision in a statement:
"As much as I enjoyed the lifestyle of a professional Aussie rules player and relished the challenge of achieving in a different code, I realised that it would never matter as much to me as the sense of community and joy I get from togging out and playing alongside the people with whom I grew up and live," Kilkenny said.
"Achieving success and realising my potential as a hurler and footballer with my club and county will always be more important to me than any of the benefits to be obtained from professional sport."
