A 10-year-old girl tried cocaine after a pupil found a stash hidden in a Pringles can and brought it to school.
Despite the potential danger, the dealer, who was responsible for the Class A drug in the tube of crisps, was spared jail.
Jamie Bartholomew, who helped train a youth football team, was arrested after pupils at Southdown Junior School in Newhaven, Hove, told a teacher about the drugs, The Argus reported.
A spokesperson for East Sussex County Council said: “Obviously this was a terrible situation that could have had disastrous consequences. Fortunately the pupils did the right thing and reported it to teachers who were able to deal with the situation swiftly.”
Christine Terry, executive headteacher at the school, confirmed no children were harmed.
"This sort of thing could happen in any school. The most important thing is what you do about it."
Bartholomew, of Newhaven, was given a 12 week suspended sentence for two years, placed under curfew for four months and ordered to carry out 150 hours of unpaid community work.