Only half the 20 Premiership clubs are managed by Englishmen. Besides Curbishley, only two English managers are in charge of clubs in the top half of the table - Sir Bobby Robson at Newcastle and Steve Bruce at Birmingham.
Given the climate against English managers, Keegan believes Curbishley's achievements are even more impressive.
"Alan has shown you can be English and successful - that you don't have to be foreign to be talented," said Keegan.
"He is the benchmark for young English managers in the way that Charlton have overcome so much and become the benchmark for clubs in financial trouble.
"Alan is a realist, he knows his club inside-out and he's got good players.
"In a way, Charlton's early problems have helped him build the club. When he first went there with Steve Gritt, the club didn't even have a ground.
"Often moments of absolute despair can help you build something and that is what Alan has done.
"Everyone has rallied together at Charlton and along the way they have given everyone hope.
"The thought of Charlton being fourth in the Premiership would have been seen as incredible in recent years.
"But they are there on merit and things might grow more difficult now because expectations will grow."
