There are plenty of great options: Giggs, Scholes, Baresi, Maldini, Facchetti, Puyol, etc.
For me though, the greatest is Francesco Totti. The others above played for clubs who won multiple trophies, and all won the champions league at least once. Aside from a smattering of Coppa Italias and one Scudetto, Totti didn’t win anything with Rome.
For me, it’s easier for a top player to stay at a top club, rather than be a top player like Totti and stay at a club that was rarely considered the best in Serie A. For my money, he is the greatest one-club man of all time.
Who would you choose?
Imma just throw in the lesser known Michael Zorc out here.
Born in Dortmund the man played for Borussia Dortmund since 1978 when he joined with 16 years of age. Ended up playing his whole career here and then continues to work as director of sports for the club. He retired from that in 2022 but that’s an overall of 44 years of service. I think he won 2 championships in the 90s as well as the Champions League in 1997 as a player then as director he won another 3 Championships with us. But mostly I commend him for playing a vital part in saving us from sinking into irrelevance after we were in dire straits around 2005. some fucking pieces of magic he performed here. buying Shinji Kagawa for 350k for example I’ll never get over how big of a transfer that was. At that point we weren’t able to do big transfers but we got somewhat creative and won a sensational title. … yeah. The club can’t be thankful enough for him.