They scored twice in extra-time to beat FC Midtjylland 2-0 and take the title with goals from captain Nicolai Stokholm and Bajram Fetai, a former refugee from the crisis in Yugoslavia.
Zuma came on in the 60th minute as the first change for the side and was shifted into a central role in midfield for the extra-time period, earning top marks from commentators.
The win for Nordsjaelland sees them through to a place in next season's Uefa Europa League.
Stokholm hit the post just after the hour but made no mistake six minutes into extra-time as he turned in a pass from Bille.
Nordsjælland doubled their lead soon after the restart, Fetai finishing smartly after Andreas Laudrup had failed with his effort to seal the victory.
"This is so big. I'm close to tears right now," said Fetai.
"This is what we've been fighting for all season and I'm not even sure that any of us have realised yet just what we've accomplished."
The former Bafana Bafana winger went back to Denmark in September to revive his career last year after flopping at Mamelodi Sundowns.
He had been a hero in Denmark with FC Copenhagen in his initial spell in the country, helping his club to win several League titles and Knockout Cups and also being named Footballer of the Year.
Zuma, who turns 35 next month, has made 13 appearances for his club this season but is used mainly as an impact player.