Theo was among the very popular Dragons thanks to his cheeky grin and funny jokes, however he decided that his time was up in 2013.
"It hasn't been an easy decision or one I have taken lightly," clarified the Greek Cypriot entrepreneur.
"The time felt to give up my seat, stop breathing flame and permit someone else to enjoy the wonderful experience of being a Dragon.
"So, it merely leaves it for me to say thank you to all previous and current Dragons. I'm Out."
Produced in Cyprus, Theo lived in Manchester and then London when his family moved into the UK from the 1960s.
Theo struggled with dyslexia as a youngster but began showing his business brain by running the school's tuck shop aged only 15.
Starting off as a tea boy and filing clerk in insurance agent Lloyd's of London, Theo subsequently proceeded into retail at age 18 and began selling watches.
By 23 he had switched into property and corporate finance and put up his own firm.
He spent in the telecom sector with the development in cellular phones and purchased Rymans as it went bankrupt and turned its fortunes round.
Theo still owns Ryman in addition to Boux Avenue and homeware pro Robert Days.
He was also Chairman of Millwall FC for eight decades, taking the team out of government and to the Championship, subsequently to the FA Cup final for the first time in their history.
Through his looks on Dragons' Den, Theo has advised many young entrepreneurs and spent in many innovative brands and businesses.
The Paphitis Charitable Trust distributes all of his fees from TV appearances, his book to causes near his heart and charities connected with kids.
The company tycoon lives in Weybridge, Surrey with his beloved wife Debbie, who he affectionately known as'Mrs P' during his time at the Den.
Theo has five children, two sons and three daughters, along with four grandchildren.
When investors were stood before him asking for cash, Theo would often ask why they needed to take away cash from his kids' inheritance.
According to last year's Sunday Times Rich List, Theo's net worth is a staggering #290million.
He returned for a guest appearance on the show in 2019 when Touker Suleyman needed a temporary illness.
Theo was made to step in for Peter while he was obligated to self-isolate during filming for string 18.