Seagull studied at Eton College, Berkshire, having applied after seeing an advertisement for scholarships at the prestigious school.
He attended the University of Oxford to study mathematics, but later dropped out, and re-enrolled and graduated from the Royal Holloway University in London instead.
He completed his teaching qualification at University of Cambridge and finished his master’s degree in education at Emmanuel College whilst finishing his newly qualified teacher (NQT) year.
In 2017, Seagull became an ambassador for the charity National Numeracy, which works to empower children and adults in the UK to feel confident with everyday maths.
After his appearance on University Challenge, he teamed up with Monkman to write The Monkman and Seagull Quiz Book, which was released in 2017.
The duo launched a TV series titled Monkman and Seagull’s Genius Guide to Britain in 2018.
Before he became a maths teacher, Seagull worked as an investment banking trader at Lehman Brothers & Nomura, and qualified as a chartered accountant from PricewaterhouseCoopers (PwC).
He has also worked with the Financial Times as a columnist and appeared on BBC Radio 4’s Puzzle for Today.