The English Premier League winner and veteran of 100 caps for Ireland has shaped a new personality in the City squad.
"Throughout my career I've probably been one of the more quiet players in the dressing room," he said.
"With age and experience you have to speak up a bit more.
"I think it needs to be done because we're a quiet dressing room at times."
Having played under the likes of Jose Mourinho, Roy Hodgson, Kevin Keegan and now John van't Schip, Duff is keen to emulate their efforts as a manager.
Taking on a mentoring or unofficial leadership role at City is moving him in the coaching direction but thankfully for City fans, he hasn't put away the playing kit just yet.
The 35-year-old would be running playmaker Aaron Mooy close in a club champion count, with memorable performances from the right wing.
Duff's five assists is second-best in the A-League, with a prolific cross count that is certain to be added to in the latest instalment of the Melbourne derby against Victory at Etihad Stadium.
He says his efforts have come through treating the A-League as seriously as his previous seasons in England.
"I knew it wasn't going to be no jolly up," he said. "It's been hard work.
"Results-wise and personally, there's been an awful lot of ups and downs.
"But we're at the business end of the season... I've thoroughly enjoyed the challenge."
Living with his wife and two children in Melbourne, Duff lights up discussing the city, despite the distance from home.
The lifestyle tempts Duff to stay another season but it's not currently in the script.
"We're going to raise the kids in Ireland, that's the plan to go home anyway," he said.
"The lifestyle for my two kids and my wife, it's been brilliant for them... it's probably the one city that's touched me the most throughout my career.
"This is my spot now, where I'll always come back and holiday."
