Marcus is the third fastest Irish man in history, over both 100m and 200m. He won bronze in the 200m at the World University Games in 2019. He ran his 200m PB at the Cork City Sports in 2018 which also qualified him for Tokyo. He was a European Junior finalist in 2015. He is a graduate of IT Carlow and is coached by his mum Patricia (nee Almond) who was herself an Irish international sprinter.