Juan Martin del Potro, who is closing in on the absent Andy Murray's world number four ranking, was also placed in Group B for the eight-man event at the O2 Arena, along with Frenchman Richard Gasquet.
World number one Rafael Nadal will be a big favourite to come through Group A given he had won a collective 35 straight matches against David Ferrer, Tomas Berdych and Stanislas Wawrinka heading into the semi-finals of the Paris Masters.
It is the second year in succession that the World Tour Finals has followed straight on from the final Masters series event of the season in France.
Last year most of the competitors at the O2 Arena lost early in Paris but this year the eight in London were also the quarter-finalists across the Channel.
That has given World Tour Finals organisers a headache, and instead of scheduling the groups on alternate days they will play one match from each group on Monday.
Berdych and Wawrinka will open proceedings on Monday afternoon, with Del Potro playing Gasquet in the evening.
Tuesday will be a repeat of the Paris semi-finals, with Nadal taking on Ferrer and then the blockbuster clash between Djokovic and Federer.
Federer will be looking for revenge after losing to Djokovic in the semi-finals in Paris on Saturday in their first meeting of the season.
It has nevertheless been an encouraging two weeks for 17-time grand slam champion Federer, who had looked a doubt even to qualify for an event he has won six times before he reached the final of the tournament in his home town of Basle last weekend.
Federer is always a danger indoors but Djokovic and Nadal will arrive in London as the men to beat.
Djokovic defeated Federer to lift the trophy for the first time at the O2 last year while it remains the biggest tournament that Nadal has not yet won.
With Murray still recovering from back surgery and Jo-Wilfried Tsonga and Janko Tipsarevic not qualifying, there will be three different names from 12 months ago.
Nadal is back after knee problems ruled him out last year, while Gasquet has qualified for the first time in six years and Wawrinka for the first time in his career.
At 28, the Swiss has enjoyed his best season, with the highlight a victory over Murray at the US Open to reach a grand slam semi-final for the first time.
Having started the year ranked 17th, Wawrinka admitted he was not even thinking about ending his season in London.
"It wasn't really a goal," said Wawrinka. "My goal was to win a tournament and come back closer to the top 10.
"But it came during the year when I started to have some great results and when I came back to the top 10.
"I played in the quarter-finals of the French Open and I was playing really well, and at that moment I saw that I had the level to stay there and to try to make it."
Wawrinka has been involved in two of the best matches of the season, against Djokovic at the Australian and US Opens, but come out on the losing side both times, while he has not beaten Nadal in 11 attempts.
"I will try every time and still think that I can beat them," he said. "Yesterday against Novak (in Paris) was a tough one but you never know what's going to happen.
"We'll see when I play Rafa. Even if you play your best tennis it might not be enough but I'm practising every day for that, to one day beat Rafa Nadal."
Even without Murray, organisers are confident more than 250,000 spectators will flock to Greenwich over the eight days, adding to the million who have already attended in the tournament's first four years.
Wawrinka is looking forward to sampling the atmosphere, and said of his fellow players: "They've told me that it's the best.
"They say it's amazing to walk on the court, the crowd is amazing and every match is sold out. It's really different to other tournaments and I'm really excited to be here and to see how it's going to be for my first match."