Calloway began his professional playing career with Wolverhampton Wanderers in 1962, but failed to make an appearance for their first team.
After two seasons with Rovers he was sent to Division Four club Southport in August 1970 in exchange for Alex Russel.
He left York to his final English club Shrewsbury Town in 1972, where he remained for two seasons.
[1] In 1978, he left the Earthquakes to coach and play for the Southern California Lazers of the American Soccer League (ASL), but was back in San Jose for the 1979 season.
With his retirement from playing, Calloway became a full-time coach, a job he would remain with for the next thirty years.
As previously mentioned, he held his first head coaching position with the Southern California Lazers of the ASL during 1978, its only season in existence.
Two years later, on 14 March 1983, the Seattle Sounders (NASL) hired Calloway as their new head coach.
The 1992 season was also characterised by antagonism between Calloway and a young forward by the name of Eric Wynalda.
On 7 December 1995, he signed Calloway as the first head coach of the new team, the San Jose Clash.
The team continued to sign previous Blackhawks players, including Paul Bravo, John Doyle and Troy Dayak.
At one point Wynalda hired an aeroplane to tow a banner demanding the team fire Calloway.
In 2002, Calloway was league Coach of the Year when he took the Menace to an undefeated regular season record.
On 18 November 2002, Calloway resigned from Des Moines to take job with expansion US second division club Syracuse Salty Dogs.