Promuto never played football until his junior year in high school, but by the time he was a sophomore in college he broke into the starting lineup at guard at Holy Cross and would remain in the lineup for three years. He earned first team All-New England and honorable mention All American honors as a senior. In his most famous game as a Crusader, Promuto recovered eight fumbles in a 14-0 victory over BC in 1957. He was also a star on the track team, as he graduated holding the HC outdoor shot put record of 50 feet, 8-1/2 inches set at the Eastern Intercollegiate meet in 1960. After graduating from HC, he was drafted in the fourth round by the Washington Redskins, and played 11 seasons in the NFL. He became one of the franchise's best linemen, making the Pro Bowl twice (1964 and 1965). Promuto captained the Redskins and in 1968 received the Outstanding Redskin Award as the player who made invaluable contributions to the team and the Washington, DC community. In 2002 he was honored as one of the 70 Greatest Redskins, and has a spot on the Redskins Ring of Fame.
He was inducted into the Crusader Football Legends Ring of Fame in 2010, as part of its inaugural class. See a Photo Gallery of the event.