Man City defender Jamal Baptiste, 20, remained stationary at traffic lights in his VW Polo for about a minute after they turned green.
He was seen inhaling the balloons with a pal in Dagenham, East London, on July 7 last year.
He pleaded guilty to driving without due care and attention and was given six penalty points and a £1,000 fine by magistrates at Bromley, South London.
He also had to pay a £400 victim surcharge plus costs of £110.
It comes a week after The Sun revealed that a Premier League star was receiving rehab treatment for addiction to nitrous oxide.
Baptiste is a former West Ham centre-back once billed as the next Rio Ferdinand by the club’s former striker Carlton Cole.
Last May the club reportedly offered Baptiste a new deal but slashed his wages due to issues off the pitch.
He moved to Man City on a free transfer in September. He is described on the club website as “an athletic and technically gifted defender who featured twice for West Ham while representing England at youth level.”