He gained admittance when he first arrived at St. Louis' League Park by pointing the gatekeeper to a newspaper photograph of himself which he had pinned to his lapel. Despite not joining the team until mid-July, he finished 10th in the National League in home runs and batted .323. The following season he hit .326 and finished 3rd in home runs with 10 while only playing in about half of St. Louis' games. On a team full of good hitters, Donlin found it difficult to get regular playing time because of his poor defense and decided to jump to the Baltimore Orioles of the new American League in to play for his former teammate in St. Louis, John McGraw. "Turkey Mike", nicknamed because of his gait while walking, hit .340 with Baltimore, which was good for second in the league. But in March of , he was sentenced to six months in prison for assaulting two people in Baltimore while drunk and was promptly released by the Orioles. After serving his time, Donlin was picked up by the Cincinnati Reds and hit .287 for them in the last month of the season. In , he finished third in the league in hitting at .351 and placed in the top five in the National League in virtually every offensive category. Donlin hit .356 in 1904, when he had another drunken episode in St. Louis. The Reds first suspended him for 30 days and then traded him to the New York Giants, where he was once again reunited with John McGraw who was now managing the team. Donlin finished out the 1904 season hitting a respectable .280 after the trade and helped the Giants win the National League pennant. His combined batting average for 1904 ended up at .329, good enough for second in the league for the second time in the career of the 26-year-old. Donlin followed up with the best season of his career in . Playing a full season for the first time, Donlin hit .356, good for third in the National League, and led the league in runs scored as well as finishing in the top 5 in several other batting categories. He led the Giants to the World Series where he hit .263 and scored 4 runs in 5 games as the Giants defeated the Philadelphia Athletics for their first World Series Championship. On April 11, 1906,