The TV exec turned presenter turned crime novelist told the Mirror he didn't take a salary for his co-host role as he continued his job as creative director of Endemol UK — the company behind the show.
Osman said: "I didn't get paid for the first four series or so of Pointless because I was the creative director of the company and I did feel like it wasn't appropriate.
"Until series four we didn't have a hit and I was still doing my job. To me [hosting the show] was a fun hobby."
Watch: Richard Osman says the Queen was a competitive Pointless player
Osman said it was the chemistry between himself and main host Alexander Armstrong which helped to catapult the show to popularity after its debut in 2009.
It has since aired almost 1,500 normal episodes as a key part of the BBC teatime schedule, alongside 250 celebrity specials at weekends.
"From the second series, me and Xander were able to talk a bit more and the ratings started picking up," said Osman.
"There was something about that relationship, the casualness and gentleness of it, that I think people liked."
Osman recently said goodbye to Pointless in order to focus on his writing career, with the third Thursday Murder Club crime novel — entitled The Bullet That Missed — released in September.
Osman will continue to appear with Armstrong on celebrity editions of Pointless and will also still front his own quiz show House of Games.
He has also recently confirmed that a fourth Thursday Murder Club book will be released in 2023 and he'll continue to write them alongside a new series he's planning to debut in 2024.
Watch: Sally Lindsay replaces Richard Osman on Pointless