The England midfielder arrived from Manchester City last week.
“First and foremost he's a very talented player and he's shown that on the training pitch already," Keane told the Liverpool Echo.
“The quality he brings, coming from a club such as Manchester City, his training standards form being there are already visible and there to see.
“After that he brings leadership qualities. I saw that when I've been away with England with him and he's already shown that in training. He's very vocal on the pitch, looks to help people out, taking the young lads to one side and giving them bits of advice. I think he's a brilliant addition and someone who, hopefully, we can get a lot out of."
Asked about Delph being vocal, Keane said: “Not in a bad way, in a good way. He really motivates players, he gets players thinking and ultimately it will improve players. He has got a lot of experience, he's won trophies, he's got a lot of knowledge about the game so he's got a lot to pass on."