Kirkham, a lightweight nicknamed "Tree" for towering at 6-feet-9, was 30.
Kirkham competed on a Dash Entertainment and King MMA co-promoted "Confrontation at the Convocation Center" event at the USC Aiken Convocation Center, a card regulated by the South Carolina Athletic Commission.
"Obviously our thoughts and prayers are with his family, other than that I have no comment," Sam King, a promoter of Saturday's card, told MMAFighting.com.
WRDW in Augusta first reported that Kirkham was transported to Aiken Regional Medical Center from the venue following the fight and was pronounced dead of a brain hemorrhage Monday morning.
Coroner Tim Carlton confirmed to MMAFighting.com that Kirkham was unconscious from the finish of the fight all the way until this morning. An autopsy will be conducted Tuesday.
Kirkham, who according to his own Facebook page, held an amateur record of 3-3, was taken down early in the fight and lost by referee stoppage from ground and pound strikes. But when he did not regain consciousness, doctors and medics attended to him in the ring and stretchered him out.
Kirkham was the captain of his own "Fayetteville Independents" MMA team and according to his teammate John Yox's Facebook page, had "severe bleeding in the brain" and had been kept on life support.
The South Carolina Athletic Commission requires that all boxers and MMA fighters submit an original or certified lab report indicating that the competitor is HIV, Hepatitis B and C negative. Also, the fighter must complete an ophthalmologic (eye) exam as well as a physical by a doctor.
Kirkham becomes the second fighter to pass away due to causes from a regulated MMA fight in the US. The first known death in a regulated event was Sam Vasquez, who died on Nov. 30, 2007 from head injuries on a local card in Houston, Texas. Vazquez was in a coma for 42 days after the fight in October.
Below is an amateur bout between Kirkham against D'Juan Owens from April 24.