Msgr Kelly, formerly the vicar general and parish priest of Killsherdany and Drung, Co. Cavan, said he was honoured to accept his new role, and would endeavour to serve the diocese until a new bishop is appointed.
Reduction in Masses from 113 to 96 over the weekend of 6 to 7 October 2018 aims to offset the decline in priest numbers and the aging profile of those still in ministry.
Of the 58 priests who are active in parishes, some 28 of these are over the age of 65. Only seven priests are under the age of 50.
Monsignor Joseph McGuinness has been appointed as Diocesan Administrator of the Diocese of Clogher, and will take up his new position immediately.
Youngest priest in the diocese, Fr Michael Geraghty, who was ordained in 2015, to head up Killaloe's social media engagement.
Appointment of Mgr Nicholas O’Mahony follows resignation of Bishop Lee on health grounds.