[1] Caldwell was notorious during his playing career for his addiction to alcohol and partying; he possessed a self-destructive streak that many of his contemporaries believed stopped him from reaching his potential.

"[3] Caldwell was born in the (now mostly abandoned) town of Corydon, Pennsylvania, located just south of the New York state line near Cattaraugus County.

[4] He began his professional career with the McKeesport Tubers of the Ohio–Pennsylvania League in 1910 and recorded 18 wins before being signed by the New York Highlanders in September of that year.

During the course of the season he had numerous run-ins with manager Frank Chance, resulting in his being fined on several occasions for drunkenness and general poor conduct.

Towards the end of the season, Caldwell asked team owner Frank Farrell to rescind his fines—which by that point accounted for a substantial proportion of his annual wages.

Donovan and the Yankees owner, Til Huston, both of whom had strongly criticized Caldwell during his absence, decided to give him another chance, largely influenced by his apparent good condition.

He was charged with grand larceny half-way through the season for allegedly stealing a ring, and was also taken to court by his wife, who sued for alimony after he abandoned her and their son.

Caldwell left the Yankees in mid-August to join a shipbuilding firm in order to avoid military service after being picked in the draft.

[5] Caldwell was struck by lightning while playing for the Cleveland Indians against the Philadelphia Athletics in 1919; despite being knocked unconscious, he refused to leave the game, having pitched 8+2⁄3 innings, and went on to record the final out for the win.

He started Game 3, but recorded just one out, having given up two hits, a walk, and an earned run, before being lifted by Tris Speaker (the Indians did not come back from this, and Caldwell was charged with the loss).

After leaving the Indians, Caldwell went on to spend many years playing for various clubs in the minor leagues, including the Kansas City Blues and the Birmingham Barons.

Caldwell bought a farm in Frewsburg in 1940 and worked at the train station at Ashville as a telegrapher for the Buffalo, Rochester and Pittsburgh Railway.