Kamui Kobayashi has revealed that he turned down the option of an improved Ferrari programme in order to sign for Caterham.
Kobayashi raced for Ferrari in the GT class of the World Endurance Championship in 2013 after failing to find a seat in Formula 1.
He also participated in Formula 1 demonstration events for the team and tested at Fiorano.
But Kobayashi says that the lure of Formula 1 racing meant that he snubbed Ferrari in favour of Caterham, despite the Italian team offering him a deal to race in sportscars and increased work on the team's simulator.
"I am 27, I still need more to race in F1, that is why I chose to come back to F1," he said at the launch of Caterham's 2014 campaign at the team's headquarters in Leafield.
"Ferrari offered me another contract, and [team principal] Stefano [Domenicali] is not happy I didn't take it. But it is only my decision to be here. I took a risk in my life but it is important for me.
"Caterham needs some different energy and my experience is quite useful for this team. We'll see what I can do. I am quite confident."
Kobayashi raised around £1m courtesy of a fans support system, which was set up after he lost his Sauber drive at the end of 2012.
The Japanese racer insists that he does not care about money and is willing to drive for free.
"I don't care about the money. I just want to be successful in my life and I want to bring the team success. This is my goal. I just say what I can do, I don't need money."
"I'll do my job. I'm very happy driving and I want to be successful in this team."