The present invention is a golf club (30) having a club head main body (34) with a hollow interior (49), a support layer 41 defining a depth of a recess (38), a polymer insert (40) in the recess (38), an isolation layer (52) and a weight body (50). The polymer insert (40) is composed of a thermosetting polyurethane material having a Shore D hardness in the range of 42 to 55, and a Bayshore rebound in the range of 51 to 60. The preferred thermosetting polyurethane material is formed from a p-phenylene diisocyanate prepolymer and a curing agent. The golf club (30) is preferably a putter, however, it may be a wood or an iron. The particular thermosetting polyurethane provides a soft striking face for feel and a good rebound for distance. The weight body (50) is preferably composed of a tungsten alloy, and the isolation layer (52) is preferably composed of a thermoplastic polyurethane.