He played six seasons in Major League Baseball with the Milwaukee Brewers (1884), Detroit Wolverines (1885–1888), Brooklyn Bridegrooms (1890), and Buffalo Bisons (1890).

Baldwin had his best season in 1886 when he compiled a 42–13 record and a 2.24 earned run average (ERA), threw 55 complete games, and led the National League with 323 strikeouts.

Baldwin's 42 wins in 1886 set the major league record for a left-handed pitcher and remains the second highest single season total by a southpaw.

Baldwin was born in 1859 in Oramel, Allegany County, New York, approximately 60 miles southeast of Buffalo.

[2][3] As a boy, he moved with his family to Barry County in western Michigan, first to Johnstown Township and then to Hastings.

[5] Baldwin began his professional baseball career in 1883 playing for the Grand Rapids, Michigan, team in the Northwestern League.

[7] Baldwin was given the nickname "Lady" because of his "quiet ways" and his refusal to swear or to come into contact with either tobacco or liquor.

[10] In 1886, the Wolverines acquired "The Big Four" (Dan Brouthers, Deacon White, Hardy Richardson, and Jack Rowe) from Buffalo and improved to second place and an 87–36 record.

[11] Baldwin's 42 wins in 1886 set a major league record for a left-handed pitcher and remains the second highest single season total by a southpaw.

During Detroit's 1887 championship year, Baldwin compiled a respectable .271 batting average and a .354 on-base percentage.

[1] He appeared in his final major league game on June 26, 1890,[1] and was released by Buffalo in early July 1890.

The injury deprived Baldwin of the full use of his right arm, and he underwent surgery at the University of Michigan Hospital to correct the problem.