The literal translation plus grand que la vie does not work indeed. It is simply one of those many idiomatic phrases than cannot be translated literally.

Truculent conveys indeed the same idea, but is a less common and more formal word than the English phrase larger/bigger than life.

Some other translations could be :

Il avait une personnalité hors du commun/hors norme

C’était un personnage haut en couleurs

C’était un sacré personnage (may sound a bit outdated to young ears nowadays…)