An earth-boring bit of the rolling cutter variety is provided with hard gage inserts that protrude from the gage surface of the cutter to engage the side of the borehole for holding gage. The gage insert has a substantially flat face with sharp cutting edges formed thereon and has cutting surfaces that define a negative rake angle with respect to the sidewall of the borehole that is being sheared by the gage insert. The cutting surfaces are comprised of multiple chamfers. The face, cutting edge, and cutting surfaces of the gage insert are formed of a super-hard and abrasion-resistant material such as polycrystalline diamond or cubic boron nitride. The body of the insert is formed of a hard, fracture-tough material such as cemented tungsten carbide. The improved gage inserts provide an actively cutting gage surface that engages the sidewall of the borehole to promote shearing removal of the sidewall material. Such an improved gage insert provides an earth-boring bit with improved gage-holding ability, and improved steerability in directional drilling operations.