In 1957 he was just fifteen years-old when he played a key part for the college in the provincial championship. A 6–3 to 3–0 defeat of Patrician College, Ballyfin gave Keher his first Leinster medal. The subsequent All-Ireland decider on 28 April 1957 saw St. Kieran's line out against St. Flannan's College, Ennis. Keher scored three goals in the second half to clinch victory, before setting up a fourth goal in a narrow 4–2 to 2–7 victory. It was his first All-Ireland medal.