Gary was born in Oklahoma City and grew up in Moore, Oklahoma. He attended the University of Oklahoma. He is married to his wife, Cathy, with whom he has 3 children and 3 grandchildren. He served as a mentor in the Columbus YMCA Leadership program.

Gary previously worked as vice president and a publisher for Brown Publishing and Athens Messenger. He also worked as a publisher of the Delaware Gazette. He also served as president of the Ohio Newspaper Advertising Executives and as secretary of the executive committee of United Way of Delaware County. He also served on the board of directors of the Copperheads, a summer collegiate baseball league in Athens.

Gary Merrell currently serves as a Delaware County Commissioner. He was elected to this position in 2012 and is serving his 3rd term. He is the president of the board of commissioners.