Leonard Ceglarski attended Boston College, for whom he played in parallel with his studies, ice hockey and baseball. Between 1958 and 1970 he was active as a coach for the Clarkson University of the ECAC Hockey. From 1972 to 1992, he supervised throughout the team of Boston College in the ECAC Hockey and Hockey East. Because of his contributions to the sport of ice hockey in the United States, he received the 1991 Lester Patrick Trophy. A year later, he was honored with induction into the United States Hockey Hall of Fame. According to him, the Len Ceglarski Award is named, which is awarded annually to the player's College Football Hockey East with the most exemplary behavior on and off the ice.
For the U.S. Ceglarski participated in the Olympic Winter Games in 1952 in part in Oslo, where he won the silver medal with his team.