Laurin’s career in thoroughbred horse racing began in 1929 as a jockey in Montreal, Quebec. After riding 161 race winners, in 1942 he began working as a trainer in New England, a job that would span 45 years and take him to the very pinnacle of horse racing success. While working for two different stables, he trained Quill, the 1958 two-year-old filly champion, and his other horses won numerous important Stakes races, including the 1966 Belmont Stakes. His son, Roger Laurin, worked as a trainer at Meadow Stable and when he accepted an offer to work elsewhere, he suggested to the Chenery family, the owner's of Meadow Stables, that his father might help them on a temporary basis. Coming out of retirement in 1971, Lucien Laurin went to work at the Meadow Stable for what was supposed to be a temporary period. At that time, the stable was having financial difficulties but things soon changed. With their colt, Riva Ridge, earning more than $500,000 and being named Champion Two Year Old Colt for 1971, Lucien Laurin and the Meadow Stable would soon become the number one stable in racing, winning numerous important Stakes races and five of the six Triple Crown races in 1972-73.
Under Lucien Laurin, Riva Ridge, with fellow French-Canadian jockey Ron Turcotte in the saddle, won the 1972 Kentucky Derby and the Belmont Stakes. A heavy rainstorm muddied the track at Pimlico, otherwise the horse may have won the Triple Crown. For 1972, Lucien Laurin was named the National Thoroughbred Racing Association’s Eclipse Award winner as North America's most outstanding trainer. However, despite this great success, Laurin is best known as the trainer of the great Secretariat who was voted Champion Two Year Old Colt, and Horse of the Year in 1972 and who, in 1973, became the first Triple Crown winner in twenty-five years and the horse considered by most as the greatest race horse ever.
Lucien Laurin retired from racing a second time in 1976, but returned in 1983 as trainer and part owner of Evergreen Stable. In all, Lucien Laurin trained a total of 36 stakes winners and was inducted in the National Museum of Racing and Hall of Fame in 1977 and enshrined in the Canadian Horse Racing Hall of Fame the following year.
Laurin was living at his home in Key Largo, Florida when he passed away in 2000 from complications following surgery to repair a fractured hip.