Markham played hurling as a student at St Flannan's College in Ennis and lined out in all grades during his time there.
After winning a Dean Ryan Cup medal in 1988, he was part of the college's senior team that won the Dr Harty Cup title in 1989 after beating St Patrick's Comprehensive School in an all-Clare final.
[2][3] Markham also lined out in the subsequent one-point All-Ireland final defeat by St Kieran's College.
[5] Markham later claimed a Munster Club IHC medal after a 0–14 to 1–08 win over Bishopstown.
[6] At inter-county level, Markham first appeared for Clare as a member of the minor team.