Osmanski was the starting fullback for some of the greatest teams in Holy Cross history, using his bursting speed, instinctive balance and awesome power to bolster one of the finest offensive threats in Eastern football during the late 1930s. The Crusaders posted a 23-3-3 record during his career, with the three loses coming by a total of five points. In 1936 his 85-yard run gave Holy Cross a 7-0 victory over Dartmouth. He had other runs of 92, 68, 65, and 45 yards, was given the nickname "Bullet Bill" and was named All-America in 1938. In 1939, he won the Most Valuable Player trophy in the College All-Star Game, before being drafted in the first round (6th overall) by the Chicago Bears.
He played for the Bears from 1939-43, and again from 1946-47. In between his two terms with the Bears, he served in the Marines in World War II . The Bears won four league championships in his time, and he led the league in rushing yardage in 1939. Osmanski, in addition to playing with the Bears, earned a dental degree from Northwestern University. He briefly returned to Holy Cross as a head coach in 1948-49 before returning to his dental practice full-time. He passed away in 1996.
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.