Brother to the trainer Patrick Monfort, Michel Monfort has ridden as a Gentleman rider in his youth but has then left the horse world for 20 years. In 2000, when he sold his food factory, he took over the 74 acres family far mat Quimperlé in Finistere, in Brittany, and has started breeding high class Thoroughbreds. His first purchase was La Toundra, who gave him a Listed winner, Gotdream (Loup Solitaire), and the sturdy Got Sky (Septieme Ciel), winner of 6 races. For this, Michel Monfort went to the Keeneland sales to find nice European lines at a better price, with the « exotic » attraction to American stallions.

This is where in 2006, he acquired a Night Shift filly named Innocent Affair, in-foal to Quiet American, for $60,000. Already the daughter ot Park Express (1st Champion Stakes Gr.1) and sister to 2 black-type winners, Dazzling Park (1st Matron Stakes Gr.3, 2nd Champion Stakes Gr.1), and Shinko Forest (1st Listed in Japan), Innocent Affair has seen her value increase thanks to the exploits of her brother New Approach. Winner of the National Stakes and Dewhurst stakes at 2 years in 2007, New Approach has then landed the Epsom Derby in 2008. Not long after, Michel Monfort has sold the first product out of Innocent Affaire by Quiet American for €220,000 at Deauville.

The same year, he has sold a son of Red Ransom out of Byre Bird for €210,000.
Michel Monfort targets the higher end of the market, purchasing mares only « daughter of »,  « sister of » or « dam of ». He offers his production at the French or English yearling sales, through the Haras du Logis Saint-Germain, du Cadran or de Grandcamp.

In August 2010, Michel Monfort had two yearlings for sale at Deauville, a son of Innocent Affair by Shirocco, and the first foal out of Rumored, the last mare he has purchased in the USA, by Hat Trick.