Singleton was born in Pennsylvania and attended Penn Manor High School where he wrestled in the 285 lb weight division.
World Wrestling Entertainment (2012)
Florida Championship Wrestling/NXT (2012)
Singleton joined WWE's developmental promotion Florida Championship Wrestling, before it became solely known as WWE NXT as Adam Mercer during March 2012. At 19 years of age, Mercer was the youngest NXT member in the program's history. Despite his impressive physical credentials, Mercer wrestled a sparse series of matches, most of which were losses to notable up-in-coming wrestlers including Big E. Langston, Brad Maddox and Erick Rowan. On August 1 in a losing fatal four-way tag match, teaming with Chad Baxter, against The Ascension (Conor O'Brian and Kenneth Cameron), Jason Jordan and Mike Dalton and Brad Maddox and Rick Victor.
Mercer's last match in WWE/NXT was on September 27 in a squash match against Erick Rowan. During the match, Mercer sustained what he described as a "serious head injury", causing him to retire. He later joined Vito LaGrasso's lawsuit against the company in 2015 (the lawsuit was thrown out by a judge in 2018.)