Michael Jordan wore number 45 when he returned to the National Basketball Association (NBA) in March 1995 because he said he would never wear number 23 again as it was the last number his father, who had passed away prior to that, saw him play in. He switched to his classic number 23 in game two of the Eastern Conference Semifinals and, as a result, the Bulls had to pay a $25,000 fine.
Michael Jordan said he dreamed of wearing number 45 when he was in high school. However, his older brother had already claimed the number. Instead, he chose the number 23 because it was roughly half of his brother's number. This is the number he wore when he first entered the NBA in 1984.