Leblanc 1987 professional team Toshiba -Look- La Vie Claire. In his first year he won the Prix de Mirebeau and was, among other things Eighth at the Dauphiné Libéré. The following year he was at the Dauphiné fourth and sixth in Paris-Nice.
In 1990 he was third in Paris-Nice for his new team Castorama. In 1991 he won a stage in the Midi Libre and ended the tour in fourth. In the same year he first participated in the Tour de France and became an instant fifth.
1992 Leblanc was a French road champion, won the Midi Libre and was second in the Dauphiné Libéré. In 1993, a rather weak season, but in 1994 he drove for his new employer Festina - Lotus have been the strongest year. He won a stage of the Tour de France, where he was fourth overall. In the fall he finished the Vuelta a España in sixth and won the mountains classification. Subsequently, he celebrated his biggest success so far: He won the individual race in the streets - Cycling Championships in Italy Agrigento. In the same year he was appointed by the sports newspaper L' Équipe France's Sportsman of the Year ( " champion of champions" ) selected.
In the following season he drove for the team Le Groupement. The team suffered major financial problems, also it got from the Directorate of the Tour de France invitation for the Tour de France. This meant that Leblanc as the reigning world champion could hardly participate in races and therefore only very rarely entered the world champion jersey in appearance.
In the same year, he joined the team Polti. He was sixth in the 1996 Tour de France and won a stage. In 1998, he finished his career after he slumped to the stage to Les Deux Alpes during the Tour de France and had a day to give up on it. Previously Leblanc had driven an attack on the Col du Galibier, which brought the leader Jan Ullrich in distress.
As part of the Festina affair in 1998 Luc Leblanc admitted in October 2000 to have doped since 1994. His success at the World Cup 1994 was won but "clean". With respect to future successes Leblanc did not make this restriction, of course.