Gattuso, who won two Champions League titles under Carlo Ancelotti, has brought the same fighting attitude to his former side since taking over in November.
Milan are unbeaten in 13 games – including reaching the Coppa Italia final - and have not conceded a goal in their last six.
“We're not Brad Pitt. We have to continue being as ugly as me and my beard, with dark circles under our eyes," Gattuso said.
“I want to clear this up, as I am not a great coach. I'm still in the early days, I'm not a guru of the bench and I've achieved nothing yet. At the same time, I am not the person that some seemed to think I was.
“You don't learn this profession through books, you learn it by getting smashed in the teeth by setbacks. I've had some and I will have many more."