On the day it was confirmed Beckham will remain with the club until June 30, Ancelotti said: "Beckham has done more than we could have possibly expected from him.
"He has settled in very well with the squad and given a huge contribution up to now.
"He is very professional and we are all very, very happy that he is staying."
The 33-year-old played in an unfamiliar support role behind strikers Filippo Inzaghi and Pato in Sunday's 3-0 win over Atalanta and, although Ancelotti admitted to being "a little worried" about playing him in a new position, he was more than happy with the result.
"He played very well," said Ancelotti. "I was a little worried about it at the start, but he is an intelligent player and knows what was required of him in that role.
"I am happy for him above all that he is staying.
"The aim was to keep him until June 30 and we have done that. He is very happy with the solution that has been found and we will make the most of having him now and then we will see."