Glenn McCuen was born on February 3, 1991, in Baton Rouge, Louisiana, to parents Glenn McCuen and Kathy Authement-McCuen. Raised in Houma, Louisiana, with his older sister, Courtney, McCuen attended Lisa Park Elementary and was active in karate until the age of 8, when he decided to follow in his older sister's footsteps and began taking gymnastics. McCuen showed a talent for gymnastics and trained at Jennings Gymnastics in Schriever, Louisiana, until, at the age of 10, the family sold everything they owned and made the move to Plano, Texas, so that he could train at the World Olympic Gymnastics Academy (WOGA).
