 In 1991, he was promoted to assistant trainer for Lukas, splitting his time between New York and Florida.Pletcher was Lukas's East Coast Assistant until fall of 1995 where he helped develop horses such as Thunder Gulch, Harlan, Serena's Song, A Wild Ride, and Flanders.He took out his trainer's license in December 1995 and saddled his first winner, Majestic Number, in February 1996 at Gulfstream Park in Florida.