What is the term for a rider who works to support his team leader?

The term for a rider who works to support his team leader is domestique.

The French word means “servant,” reflecting the rider’s team-first role. A domestique may fetch water and food, set the pace, shield a leader from wind, chase down attacks, or give up a wheel or bicycle after a mechanical problem. These tasks conserve the leader’s energy and protect their position.

Domestiques are especially important in stage races such as the Tour de France. Mountain domestiques control the pace on climbs, while lead-out riders guide sprinters toward the finish. Some are experienced “super-domestiques” or lieutenants who remain with a team leader during decisive moments.

The role does not mean a rider lacks ability. Chris Froome supported Bradley Wiggins before becoming a Tour winner himself, and Greg LeMond had previously ridden in support of Bernard Hinault. Terms such as rouleur, sprinter, and puncheur describe riding specialties, not the specific support role.