The Irishman played for the Seagulls from 1988 to 1996, before also playing for Oxford, Wycombe and Ebbsfleet.
Former team-mate John Byrne tweeted: "Devastating news regarding Paul McCarthy. One of the nicest most genuine lads I ever played with. Thoughts are with his family. RIP Macca x"
Kerry Mayo tweeted: "Absolutely gutted! One of the nicest guys in football and always made time for me as a youth player #RIPBarrelChest."
Ahead of The Goldstone Years - 20 years on show at The Theatre Royal in Brighton, Garry Nelson tweeted: "On a big reunion night for us ex-#BHAFC players, terrible news just announced about our former team-mate Paul McCarthy - RIP Macca."
McCarthy captained Ebbsfleet to the FA Trophy in 2008 and was then assistant manager to Liam Daish, who tweeted: "At a loss for words at the news my skipper, my assistant, my mate Paul McCarthy has passed away. Sleep well big man. R.I.P."
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