The Los Angeles Galaxy player joins the Italian side until March as he attempts to stay fit in the US close season.
And after the Englishman was paraded in front of the San Siro crowd on Sunday, Ancelotti made it clear that the move was more than a publicity exercise.
"Certainly there is a place for him because he is a great player," said the Milan coach.
"He is very well-prepared tactically and he can give a contribution to this team.
"He is in good condition and if he is one of the 11 names on the team sheet, then it is because he deserves to be there.
"I met with him this morning and he has been welcomed very well. We are all delighted to have him here.
"We are all happy because what we have got is a great professional."
Speaking on Saturday, Beckham said a key reason behind the loan was the relatively short length of the football season in the United States.
"I've always said I would miss playing at the highest level," said the 33-year-old.
"I'm not saying that in America they won't get to the highest level - it will take time and it will happen - but with five months off during the season I personally can't do that."
Beckham, who has 107 England caps, needs to remain fit to keep his place in England squad as he bids to surpass Bobby Moore's outfield record of 108 caps.
"I know how (England coach) Fabio Capello works," said Beckham. "If you're good enough and working hard enough, you'll be in the team no matter where you are or where you're playing.
"You should not be given England caps lightly, they're very precious. People have questioned that in the last few games I've played in which is quite unbelievable considering I'm on 107 caps.
"To be up there with Bobby Moore is an incredible thing. If I end up equalling the record, I'd be even more honoured but at the moment I take each game as it comes."
Capello - a former coach of AC Milan - said on Saturday: "I put [Beckham] in the squad when he played with LA and if he plays for AC Milan it is possible he will be in the squad.
"Beckham's record is not important for me - I decide the squad to win a game, not for the record."
And Beckham, who began Saturday's news conference by addressing the assembled media with a few words in Italian, admitted: "I needed to be able to be playing top-flight football to keep myself fit, to keep myself in contention for other things that are going on."
The first game Beckham could potentially play for Milan is their away match against Roma on 11 January.
"I wouldn't have taken this opportunity if I didn't think I could help the team," said Beckham.
"It's not about anything else apart from the football. I've come here to play with some of the best players in the world.
"To be able to step on to the training field with Kaka, (Andrea) Pirlo, (Paolo) Maldini, Ronaldinho - there's so many players that I've always watched and played against but never played with.
"There's some great players out there and I don't expect to walk in on the first day and be starting in the team, it doesn't happen like that.
"I'm going to work hard in training, I'm going to get my fitness - because I need to - and then once I'm fit, hopefully I can get some time in the team, and hopefully help.
"I know there's quite a few injuries at the moment," he added, referring to a lengthy injury list that includes the likes of Kaka, Pirlo, Gennaro Gattuso and Mathieu Flamini.
Beckham, who will wear the number 32 shirt, is especially keen to line up alongside 40-year-old defender Maldini.
"What is great about AC Milan is the history of the club, that's what makes great clubs," said the Englishman. "Who better to represent the club than Maldini?
"He's still playing at top level. That just shows the club's amazing structure, amazing beliefs in players whether they're young or old. As long as they're talented it doesn't matter.
"I've played against him and know how good he is. Now to play with him, well it's a huge honour.
"I love the history behind great teams, I've said it before. I loved playing for Manchester United.
They will always be the team that gave me my start, gave me the chance to win so many trophies.
"I fell in love with Real Madrid too and now that I've seen AC Milan, I'm already falling in love.
"It's going to be hard to leave but I'm going to have a great time here I hope."
Earlier on Saturday Milan suggested they would consider signing Beckham on loan again in 2010 if his two-month spell goes well.
"We hope Beckham leaves an indelible mark," said chief executive Adriano Galliani. "Next year we could repeat the experience, maybe for longer."
Galliani had previously hinted that Beckham may want to spend more than two months in Serie A but the chief executive played down the speculation.
"David Beckham will stay with Milan up to 9 March. The last match is Milan v Atalanta on 8 March. I don't want to delude anyone," he said.
"He will be here with us for nine Serie A games and will also play some friendlies.
"We will then consider whether to include him or not in our Uefa Cup squad because eventually he would only be able to play up to the first and second leg of the last 16 of the competition.
"We will make this decision by the end of January."
Prior to his official unveiling Beckham had a medical at a private clinic.
Source: BBC
AC Milan captain Paulo Maldini has expressed his admiration for David Beckham after he completed his first training session with the club.
