The Saturday Night Project is an evening for 13-19 year-olds to take part in various activities and sports including badminton, body zorbing, squash netball, Zumba® and table tennis.
Many regular events had taken a break while the centre was used as a training facility for volleyball teams during London 2012.
Twelve nations, including Team GB used the sports hall, which was given £250,000 of Olympic funding for improvements.
Sobell Leisure Centre manager Damien Swan said: “It was great to see so many young people enjoying themselves and taking part in activities in a fun and safe environment.”
Cllr Janet Burgess, executive member for health and wellbeing for Islington Council, said: “The Sobell Centre’s sports hall is now fully open for our residents, and has probably never looked better.
“We’re committed to helping residents live healthy, active lives, and the Olympics have brought a real legacy for the Sobell and our residents, with great, improved facilities.
“It was wonderful to welcome Olympic athletes to our borough, and its wonderful local people will be using the same top-class sports hall.”
The Sobell Leisure Centre was the brainchild of Islington businessman and philanthropist Sir Michael Sobell, who set up a charity to build and manage the leisure centre in 1970. In 2010, a plaque was to unveiled to commemorate Sir Michael’s work.
The Saturday Night Project takes place on the last Saturday of each month running from 6-10pm, entrance fee is £3.