Since his appointment last weekend Di Canio has been forced to distance himself from comments he made in the past in which he described himself as a fascist, claiming in a club statement earlier this week that he does not support the ideology of fascism.
Speaking about his appointment, Redknapp, who managed Di Canio at West Ham between 1999 and 2001, said: It's fantastic, I'm delighted for him.
"Paolo's off the wall. He's volatile but enthusiastic and you want enthusiastic people around you in life.
"He's up for it and loves it when he wins. Hopefully from his point of view it will rub off on the players. They'll become more enthusiastic and the crowd will get involved.
"He's a great trainer and is super fit. I heard the new manager of Swindon said he can't believe how fit the players are....he can't believe he has taken over a squad that is so fit. I can believe that with Paolo."
Redknapp also admitted to being unaware of Di Canio's political views but brushed off talk that the Italian was a racist.
"I'd be a liar if I could sit here and tell you that I knew what a fascist was," Redknapp said.
"I'm sorry, I'm not educated enough so I couldn't tell you what their beliefs are.
"I don't know what Paolo's beliefs are, he's not a racist, that's for sure and is important.
"I've never discussed anything like that with him. I honestly didn't know that he had views that were different.
"It's amazing how suddenly he's a fascist now he's at Sunderland and wasn't at Swindon.
"No one mentioned anything about him when he was at Swindon, suddenly he goes to Sunderland and all the dirt in the world gets dug up on him.
"Why didn't someone write about it when he was at Swindon if it's upsetting everyone?
"I'd love him to do great at Sunderland, I really would. He was a great player for me, a good lad, a great trainer, the fittest guy you would ever wish to see.
"He will want his players to be the same, to live right, conduct themselves and eat right and be as fit as they could ever be. He will demand that from them.
"Like I said, no one started on him when he was at Swindon, as soon as he goes to Sunderland people start digging things up about his past.
"He was loved at West Ham, he was absolutely idolised by the fans. He was a fantastic player.
"I don't know (if he will keep them up). He has a tough job on his hands, but he will give it his best shot."
Although the media reaction was far less pronounced when Di Canio was appointed by Swindon, the Italian's previous political statements did cause the GMB trade union to withdraw its sponsorship of the club.
Stoke manager Tony Pulis was pragmatic about the Black Cats' decision to sack Martin O'Neill and install Di Canio.
"Clubs have to do what they have to do, and if the chairman of Sunderland wanted a change of manager, then he has changed it," Pulis said.
"He owns and runs the football club, and that is his decision, and then everybody has to get on with it.
"Martin will have been disappointed. I think there are a lot of people in football who were surprised and probably disappointed for Martin.
"The king is dead, long live the king. That's the way football management is."
On Di Canio's arrival, Pulis added: "They have seven games to go and we'll see. I'm sure the press and media are delighted to have him on board."