Career
A tight end, he played collegiately for Colgate University, and professionally for the American Football League"s San Diego Chargers from 1961 through 1969. He also played one year for the National Football League"s Oakland Raiders. He was on the Chargers" 1963 American Federation of Labor-Congress Championship team in their victory over the Boston Patriots.
He was an American Federation of Labor-Congress All-Star in 1966 and 1968.
His Chargers head coach, Sid Gillman, employed MacKinnon with Dave Kocourek in the first "twin tight-end" formations seen in professional football. MacKinnon was out of football when he died in 1975.
After fleeing the scene of a car accident and apparently drunk, MacKinnon jumped over a tall fence, not knowing about the construction site on the other side. MacKinnon fell some 30 feet and died of injuries caused by the fall.