Nicknamed "Happy Jack", Chesbro played for the Pittsburgh Pirates (1899–1902), the New York Highlanders (1903–1909), and the Boston Red Sox (1909) of Major League Baseball (MLB).

If one demarcates 1901 as the beginning of major league baseball's modern era, Jack Chesbro holds the modern era major league historical single-season records for wins by a pitcher (41), games started by a pitcher (51), and complete games pitched (48).

John Dwight Chesbro was born on June 5, 1874, in Houghtonville, a village in North Adams, Massachusetts.

That year, he pitched for the Albany Senators of the New York State League until they folded, at which point he joined the Johnstown Buckskins.

After the season, on December 8, 1899, Chesbro was traded with George Fox, Art Madison, John O'Brien, and $25,000 ($915,600 in current dollar terms) to the Louisville Colonels for Honus Wagner, Fred Clarke, Bert Cunningham, Mike Kelley, Tacks Latimer, Tommy Leach, Tom Messitt, Deacon Phillippe, Claude Ritchey, Rube Waddell, Jack Wadsworth, and Chief Zimmer.

[18] The Louisville club dissolved that offseason, and Chesbro, Fox, Madison and O'Brien were assigned to Pittsburgh in March as the National League (NL) reduced from 12 to eight teams.

Chesbro agreed to sign with a new AL franchise, the New York Highlanders (presently known as the New York Yankees), for the 1903 season, for a $1,000 bonus ($35,215 in current dollar terms) to join the AL.[21] The news broke when Jesse Tannehill, who also agreed to join the Highlanders, told Pirates owner Barney Dreyfuss about the planned defection while under the influence of pain medication.

[27] Chesbro won 14 straight games from May 14 through July 4,[28] a New York franchise record that stood until Roger Clemens broke it in 2001.

Even after Chesbro's death in 1931, his widow, with the support of former Highlanders manager Clark Griffith, continued to claim that the pitch was a passed ball, and blamed the winning run on catcher Red Kleinow.

At third base, Chesbro mistakenly thought he had received a steal sign from manager Clark Griffith, while Willie Keeler bunted for a hit.

[12] Prior to the 1909 season, Chesbro was assigned to the Indianapolis Indians of the American Association, a minor league affiliate of the Highlanders.

[43] The Red Sox returned Chesbro to the Highlanders prior to the 1910 season, but he was placed on the ineligible list after he refused to report to the minor leagues.

[45] Chesbro met with Highlanders owner Frank J. Farrell and new manager Harry Wolverton in February 1912 about attempting a comeback.

That year, the Veterans Committee elected eleven players: Chesbro, Jesse Burkett, Frank Chance, Johnny Evers, Clark Griffith, Tommy McCarthy, Joe McGinnity, Eddie Plank, Joe Tinker, Rube Waddell, and Ed Walsh.

The only other 40-win season since 1900 was 40 by Ed Walsh in 1908, and only three other pitchers in the modern era have won as many as 35--Christy Mathewson (37 in 1908), Walter Johnson (36 in 1913) and Joe McGinnity (35 in 1904).

[53] Dan Holmes, who runs the Hall of Fame's website, called Chesbro "one of the best pitchers in the game at that time.

[55] Baseball historian Bill James considers Chesbro to be undeserving of induction to the Hall of Fame.

[56] In particular, James compared Chesbro's statistics to those of former Pittsburgh Pirate teammates Deacon Phillippe (189–109, 2.59), Sam Leever (194–100, 2.47), and Jesse Tannehill (197–117, 2.80), none of whom are in the Hall of Fame.

In his book The Politics of Glory, James charged that the induction of undeserving players created a "second tier" in the Hall of Fame.