He is the son of Jane I. (Martin) and Philip J. Taptiklis. Theo is of one quarter Greek descent, with the rest of his ancestry being English and Scottish. Theo's paternal grandfather, Nicholas Theodore Taptiklis, was born in Greece, while Theo's paternal grandmother, Barbara Jean Dorothy (Keech), was English, born in West Derby. Theo's paternal grandparents moved to New Zealand, where his father was raised. Theo's mother's family is from Glasgow, Scotland.
A previous job Theo held was working at the National Health Service in England. His job was to go to the homes of the recently deceased and clean up any bodily fluids left behind.
Theo has been a part of multiple bands including Makora and Shere Khan.