The broadcaster and Manager of RTÉ Raidió na Gaeltachta’s service in Donegal died on Monday evening.
Séamus was very involved in the community, and was the Secretary of the Gort an Choirce Committee for many years.
He is survived by his wife Dolores, their three children Dónal, Éadaoin and Póilín, a brother and sister, relatives and friends.
Edel Ní Chuireáin, Ceannaire RTÉ Raidió na Gaeltachta, said: "It is with great great sadness that we learned of the death of Séamus Mac Géidigh.
"He was a man amongst men, a mentor and champion of his staff here in Doirí Beaga, a community leader, a talented broadcaster, a gifted commentator, a family man and a friend to us all here.
"This service will be all the poorer for his loss, as will the community in Donegal.
"He will be sadly and greatly missed. May he rest in peace. We extend our sincere condolences to his wife Dolores, to his children Éadaoin, Dónal and Póilín, and to his relatives and friends."
Commenting on the death, Acting RTÉ Director General Kevin Bakhurst said: "I'm deeply saddened to hear the news of Séamus' death. He was a highly respected journalist and broadcaster and will be greatly missed by colleagues across the organisation. My thoughts and condolences are with his family and friends at this time."