Mr Tony Chee, 35, has worked as a physics teacher, a curriculum researcher at the National Institute of Education (NIE) and was a senior head at the Ministry of Education (MOE).
The Public Service Commission (PSC) scholarship holder did his undergraduate studies at the University of Birmingham in Britain, and graduated with first-class honours in physics and mathematics.
And now, Mr Chee can include physics tutor to his already impressive resume, having done the job full-time since last year.
Mr Chee, who is married with a two-year-old daughter, decided to become a private tutor as he craved for more flexibility, as well as more time to pursue his interests.
He currently tutors secondary and pre-university students in physics, and holds classes in Bukit Timah and Marine Parade. But establishing the tuition business was initially tough.
Mr Chee took a pay cut when he started out and had to bear the cost of setting up the premises where classes are held.
He declined to say how much he earns, except that it is modest compared with his peers. Currently, he gives tuition to about 70 students, and his fees range from $260 to $340 a month.
Mr Chee, who is familiar with the strategies required to score well in physics, taps his experience to help his students. At NIE, he did research on improving curriculum and pedagogy. When he was at MOE, the former senior head of the higher education division managed university matters.
"I try to clear up common misconceptions and give guidance on the concepts likely to appear in the exams," said Mr Chee.
He also gives his students his mobile number, so that they can text him when they encounter gaps in their understanding.
Almost all the students from his batch of students last year attained better grades. Nearly two-thirds made three or more grade jumps.
"It depends on the students. If they are willing to work hard and be open to learning, then the pace of improvement is faster," he said.
"Ultimately, students come for tuition to learn better and achieve better academic performance."
Some of his classes are currently oversubscribed but his class sizes are kept small - each class comprises about seven students.
Mr Chee believes there is a strong demand for tuition in Singapore. He said: "If there is someone who can guide you on how to do a job better, why wouldn't you give it a try?"