Federer, a nine-time Grand Slam winner, will meet either Fernando Vicente of Spain or a qualifier, after having a bye in the first round.
"My preparations have been good again. I came off playing very well in the Davis Cup and I had a few days off, arrived here very early - arrived here Friday morning and I'm playing on Wednesday," said Federer.
The 25-year-old, who won his third consecutive US Open title last month, drew a crowd of over 1,000 screaming fans to his first practice session, held on centre court.
"It was really great fun to have my practice announced officially at 10 a.m. on centre court," Federer told reporters.
"I can't remember ever having that. We had ball boys and everything. The only thing missing was the umpire!"
Spain's Tommy Robredo is seeded second behind Federer in Tokyo with British players Andy Murray and Tim Henman also in a strong draw at the $765,000 tournament.
Federer is set to meet top British player Murray in the semi-finals, but the Swiss star admitted he hadn't even seen the draw.
"If somebody gives me the draw I'll have a look at it," said a smiling Federer.
"I always look maybe two or three rounds ahead and then I'll know who'll still be around. But I try not to get too excited. My focus is not on Andy - it's the entire tournament."
For someone who has had so much success in a short period of time, Federer stressed that he was still hungry for more and that his motivation to play great tennis was still there.
"I'm only halfway through my career and I have a lot of tennis left," Federer said.
"My motivation has always been to win grand slams and be number one.
"All of a sudden to lose my motivation while I'm at the top is not something that makes sense."
Early first round results in Tokyo saw Danish player Kenneth Carlsen defeat local Goichi Motomura 6-7, 6-3, 6-2, Argentina's Edgardo Massa beat Greece's Konstantinos Economidis 6-1, 6-3, and Wang Yeu-tzuoo from Taipei securing victory against Kevin Kin from the USA 6-3, 6-1.