Born in 1940 in Syosset, New York, Michael Plumb got his start with the Meadow Brooks Hounds Pony Club where he earned his "A" rating. He began his career representing the U.S. in the sport of eventing at the 1959 Pan American Games, which took place in Chicago. He was named to a record eight U.S. Olympic teams, riding in his first Olympic Games in 1960 at the age of 20. He was named to every Olympic three-day eventing team from that Games through 1984, earning six medals: team silver in 1964 at Tokyo on a catch ride; team silver again in both 1968 and 1972; team gold and individual silver in 1976; and team gold again in 1984.

"Mike was the rider you wanted to go into the trenches with," said Jimmy Wofford, who rode with Plumb on the 1968 and 1972 Olympic teams. "You knew he was going to finish and that he was going to finish with a good score."

Plumb was also a member of several Pan American Games squads, winning team gold in 1963 and individual and team gold in 1967. His international career also spanned several World Championships, including team and individual silver medals in 1974 and team bronze in 1978 and 1982.

Plumb comes from a family of riders. His father, Charles Plumb, was a prominent steeplechase rider, and Plumb himself placed second in the prestigious Maryland Hunt Cup in 1977, a race his father had previously won. Plumb’s son, Charlie, has also been quite successful in eventing.

During his career, Plumb earned the USEA's Rider of the Year Award 10 times and has trained his students to achieve the same award.