Mr Tnay Teng Long graduated in May from the Republic Polytechnic (RP), but he still returns to school weekly to help tutor his juniors.
The 29-year-old graduated this year as RP's most outstanding student from the Institute of Technical Education (ITE), with a grade point average (GPA) of 3.81 out of 4.
But he had to overcome setbacks such as failing his English O-level paper and retaking it, and dropping out of two polytechnics at different times.
Mr Tnay is now working as an IT operations executive as part of the Earn and Learn Programme in cyber security, offered by Singapore Polytechnic (SP).
"If not for ITE, it could have been a different story for me... ITE gave me the foundational skills and confidence to further my interests and learn how to socialise," said Mr Tnay, whose mother is a factory worker and late father was self-employed. He has two older sisters.
Fitting in was a problem when he had his first taste of poly life in 2006.
He said: "In secondary school, you mostly stick to a class so you're familiar with people. But in poly, you have to mix with a wider group of people."
He left RP after three to four months. He decided to "give ITE a shot" the next year, and did well in his higher Nitec in information technology with a GPA of 3.6.
After national service, he enrolled in SP to study aerospace electronic engineering but did badly in exams, so he left after a few months.He decided to go back to RP to take up a course he was interested in: business information systems.
Ms Mary Yeo, who taught Mr Tnay, said: "He's a gem - and very mature, self-driven, interested to pick up new skills and share knowledge. His life experiences in education and national service helped him grow in maturity."