The Black Cats are firmly in the race to sign Gateshead-born Swansea striker Danny Graham this month amid reported competition from Norwich, QPR and Reading, with much being made of the 27-year-old's affection for arch-rivals Newcastle.
However, while declining to comment on his interest in the player - a formal bid has now been tabled - O'Neill is confident any prior affiliation goes out of the window when a professional pulls on the colours of another club, and he has hard evidence to support his argument.
Northumberland-born Bob Stokoe, the man who led then second division Sunderland to their FA Cup final over the mighty Leeds 40 years ago, was part of the famous Magpies team of the 1950s before crossing the divide, and his place in the club's history has been marked by a statue at the Stadium of Light.
O'Neill said: "You can grow up supporting a team, that's the nature of it, but when you become a professional player, then that is your job.
"Your job then is to play the best for your team, and I think that's the case. There is a statue outside the football club here to a Geordie, so there we go. It can't be bad, seriously, I am being really serious."
O'Neill added with a smile: "If you can do some things for the football club, the fans are willing to forgive and forget."
Graham would not be the first man with Newcastle connections to accept an offer of employment from Sunderland - Len Shackleton and Bob Moncur famously played in both black and white and red and white, as did Paul Bracewell and Barry Venison.