In 1953-54, he played the entire season for the New York Rangers, but then spent most of the next four seasons right back in the minors, having lost the starting job in New York to Gump Worsley. During his 14 years in the minors, he won the Les Cunningham Award as the AHL's best player three times and the Hap Holmes Award for top goaltender another three times. Bower's big break came in the summer of 1958 when the Leafs claimed him from Cleveland at the Intra-League Draft. Bower was at first reluctant to join the Leafs, even though they had finished in last place the previous season, telling them he could be of no help to the team. It was only after being threatened with suspension that he showed up for training camp that fall, and within days he had established himself as the team's number one goalie at age 34. He played a total of 12 years with the Leafs.
Bower, like his other five Original Six brethren, became famous for his fearless play. Maskless, he never shied away from an attacking player and in fact patented the most dangerous move a goalie can make - the poke-check. Diving headfirst into the skates of an attacking player at full speed, Bower would routinely flick the puck off the opposing player's stick and out of harm's way. One time he got a skate in his cheek, knocking a tooth out through his cheek. He suffered innumerable cuts to his mouth and lips and lost virtually every tooth in his mouth from sticks and pucks, but almost to his last game, he never wore a mask. And under the confident eye of coach Punch Imlach, Bower got better and better. He led the Leafs into the playoffs in his first season with a miracle comeback to end the schedule, and then lost two finals in a row before winning three consecutive Stanley Cup championships - 1962 to 1964. At this time, Imlach noticed that Bower was having trouble with long shots and ordered his keeper to undergo an eye exam. Sure enough, Bower was shortsighted. But Bower refused to retire, teaming with Terry Sawchuk to win the memorable 1967 Cup with Toronto's Over-the-Hill Gang of players, led by the 43-year-old Bower himself.
After he retired in 1970 as the oldest goalie ever to play in the NHL, Bower remained with the Leafs for many years as a scout and then goalie coach, putting the pads on and helping Leaf goalies in practice.
At one injury-riddled time during the 1979-1980 season, he came within a whisker, at age 56, of dressing as the team's backup.
A member of the Hockey Hall of Fame, Bower is one of only a select few to have his number honoured by the Leafs.