How would you say a person has made a choice out of being of noble character?

Let us say a person is noble/of noble character/noble-hearted. As in, he isn’t a person of a social rank of nobility, but rather is a good, selfless person.

I’d like to say that this person has done a great thing out of his noble character. Would I be able to say "He decided to stay out of nobility"? – or would that imply noble in the meaning of social rank?

If not, how would I say it?