Billy Maloney originally came up as a catcher when he made his MLB debut for the Milwaukee Brewers of the American League in 1901. He remained on the club when they moved to St Louis and became the Browns for the 1902 season. He finished the season with the Cincinnati Reds of the National Legue. He started the transition during the 1901 season and by the end of 1903, he was a full time outfielder. In 1903, he was playing in the minors for the Minneapolis Millers and the Kansas City Cowboys of the American Association. The next year, he was a full time OF for the Millers, playing 150 games and hitting .317 with 197 hits, 28 2B and 12 3B.
Known for his speed, Maloney joined the Chicago Cubs of the NL for the 1905 season. He led the league in stolen bases (59) as well as strikeouts (84). In 145 games, Maloney hit .260 with 17 2Bs, 14 3Bs and 2 HR to go with his 56 RBI. For the 1906-1908 seasons, he played for the Superbas, but hit just .221 and .229, respectively, for the 1906 and 1907 seasons. Because of his struggles offensively (he led the NL in Ks in both 1906 and 1907), the Superbas looked at the 30 year old as more of a 4th OF and utility player. Still a threat to steal a base- but no longer a regular- the Superbas started to use Maloney as a catcher, a position he had not played since 1903 in the minors. According to the story, after allowing all those stolen bases to the Giants on 9/9/1908, Maloney left the team never to play in the major leagues again. However, Maloney would spend until 1914 in the minor leagues and was paid very well because of his MLB service time.