The League Two side confirmed the 39-year-old’s departure on Monday afternoon, with the ex-Blues defender’s exit coming with immediate effect.
Chorley had been the Robins’ director of football for less than a year, having been appointed to the role in July 2021 – on the same day that Ben Garner was named as manager.
The duo were credited with turning Swindon into promotion contenders last season after arriving with just six players to work with in the summer.
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Garner has been heavily linked with the vacant manager’s job at Charlton and is also expected to leave the County Ground outfit.
Before his role as director of football, Chorley operated as chief scout for the Robins.
The former Arsenal centre-back made 31 appearances for Pompey after being recruited by Richie Barker in January 2014.
Yet following a solid start, his performances dipped and the ex-captain left in the summer of 2015, with incoming manager Paul Cook initiating an overhaul.
Chorley went on to spend three seasons at non-league Bromley, before retiring and turning his attention to working in football recruitment.