The 17-year-old beat 13 other students, who gained Britain's best GCSE results, to receive the GCSE Student of the Year Award.
The Bolton teenager was stunned when a letter arrived with her music exam results telling her she come top out of 18,000 students.
She told The TES: "I was walking around the house in a bit of a daze. It was a complete shock.
"Revising for the exams was really hard, I was tired and stressed all the time, but coming up here makes it all worth it."
Each year the country's biggest exam board, the Assessment and Qualifications Alliance (AQA), rewards students for their outstanding exam performance.
George Turnbull, of AQA, said judges picked Katie because she had also earned A* grades in 11 subjects, the only one in the group to do so. She received a gold medal and a pound;100 cheque at a London ceremony this week. The other pupils received silver medals.
Her parents, Sandra and Mark were surprised by their daughter's achievement.
"We knew she would do well as she has always worked hard, she is very conscientious and focused but we never expected her to do as well as this," said Mr Telleck.
Katie plays the piano and flute and is a member of the Bolton Youth Concert Band and the Bolton Youth Orchestra.
But the talented teenager's ambition is to become a doctor. She has decided not to continue her music studies instead opting to do AS-levels in chemistry, biology, French and English.
Frank Vignon, Katie's head at Turton media arts college, said: "It's the first time a student at the school has won the award. It could not have happened to a nicer girl."