Quillon was born in 1970 and grew up in the South West. He has been a Christian since 1979 and is married to Sandy. They have three children and have lived in Wallingford since 1993. Quillon works as a Principal Scientist at HR Wallingford, specialising in Hydroinformatics. He studied Mathematics at Brunel and Bath Universities.

Quillon plays the guitar and likes board games, history and archaeology. Sandy works in the education sector, having also been a Staff Nurse at the Churchill Hospital in Oxford specialising in home dialysis. She plays the piano, guitar and saxophone.