[2] On the evidence of practice matches, the Kentish Mercury wrote that Caldwell appeared to be just the left back Arsenal needed: "a safe tackler, can keep the forwards off his goalkeeper, has a good pace, and is very clever at overhead kicking.
"[3] He must have justified the opinion, because he was ever-present through the 1894–95 season and missed only one match in the next, in partnership with regular right-back Joe Powell.
[4] Caldwell was suspended sine die in the second half of the season, but reinstated on reduced wages around the time that manager Thomas Mitchell resigned,[11] and he finished the campaign playing at right back.
[4] He began the 1898–99 season with the newly formed Brighton United of the Southern League, and played 45 of a possible 49 competitive matches, but then returned to Scotland with junior club Galston.
He was a regular in the side for three seasons, and captained the team as they gained promotion to the Southern League First Division in 1902–03, but played only reserve-team football in 1904–05, after which he left the club.