William “Peeney” Mills was considered one of the top catchers in amateur baseball in Ontario in his day, when he backstopped the Grand Trunks and the Nationals to Senior Baseball championships. A life-long resident of Belleville, “Peeney” played first base for the Belleville Ontarios, winners of the Belleville Senior League in 1910.
He was signed as a catcher for the Grand Trunks in 1919, the year they won the Ontario Championship. He had many offers to turn professional at that time, but rejected them to remain in Belleville. In 1928, he was behind the plate when the Nationals own the Senior Provincial title. For a number of years, he played hockey for junior and city league teams. He was names to the Ontario Athletic Commission in 1934, and hung up his mitt the following year.
In 1940, the Ontario Baseball Association honoured him as the best amateur baseball catcher for the previous twenty years. In addition to his playing, he was a much respected manager.