Dundee born left back Jack Chaplin started his football career with hometown junior clubs Dundee Arnot in 1901 and Dundee Wanderers in 1902 before joining Dundee in 1903. After two years at Dens Park he moved South to join Southern League Tottenham Hotspur in 1905, making his Spurs debut in a Southern League fixture at Portsmouth in April 1906 and making 67 appearances for The Lilywhites before returning to Dundee in 1908. At Dundee he won The Scottish Cup in 1910 beating Clyde in a Final which required two replays, and he also represented The Scottish League against The Irish League in a 2-0 victory at Firhill in October 1909.
After 88 League appearances for The Dark Blues across his two spells with the club, he joined First Division Manchester City in the 1910 close season making his Football League debut against Nottingham Forest that November and making 17 appearances for The Citizens over a single season spell at Hyde Road. He later joined Leeds City spending 1913-14 with them without making a first team appearance.
He had a spell as trainer of Bristol Rovers before becoming the trainer of Huddersfield Town under the management of Herbert Chapman during their glory years of the early-mid 1920’s. Chapman left for Arsenal in 1925 and was succeeded for a season by Cecil Potter who guided Huddersfield to a hat-trick of League titles. Chaplin is most noted as the man who then succeeded Potter as manager of Huddersfield Town in August 1926, leading them to runners-up spots in the League Championship in 1927 and 1928, as well as to the FA Cup Final in 1928 where they lost to Blackburn Rovers. In 1929 they got to the FA Cup semi final where they were beaten by eventual winners Bolton Wanderers at Anfield. He left the post in May 1929.
His brothers Alec, who played for Dundee United and Fulham, and George, who played for Bradford City, Coventry City and Scotland, were both professional footballers.