Hanamy made his senior hurling debut for Offaly in 1987. From 1988 to 1990 he collected three consecutive Leinster titles; however, Offaly were defeated in the subsequent All-Ireland semi-final on all three occasions. In the 1989 All-Ireland semi-final Offaly embarrassingly lost to an unfancied Antrim who were later trounced by Tipperary in the championship decider. Two years later in 1991 Hanamy captured a National Hurling League title, Offaly's first. Three years later in 1994 Hanamy was captain of Offaly and he won his fourth Leinster title. Offaly later progressed to the All-Ireland final where they played Limerick. With four minutes to go Offaly were trailing by five points; however, a scoring spree in the remaining time resulted in the side actually winning the game by 6 points. Offaly manager Éamonn Cregan had orchestrated a great win over has native county and Hanamy finally collected his first All-Ireland medal.