"Depart from evil, and do good; seek peace, and pursue it." Psalms 34:14-15
No, it's Valjean's character that makes him the star. Not just the fact he is the MAIN character of the story, but, he makes a dramatic change by the end of the film. And that is what a well written character will do.
It seems all the other characters move about him, as if in a dance, but each one remains the same. If they were sweet, they remained sweet. If they were greedy, they remained greedy. If harsh and unfeeling, they remained so until the end.
Valjean, putting his past behind, has determined with God's help, to make up for all the sins he has committed. He goes about doing good wherever he may be. Twice he is called a saint. Once by Monsieur Fauchelevant, when Jean rescues him with Herculean effort from underneath the cart, and by Fantine, when she is on her deathbed, knowing Valjean has vowed to look after her daughter, Cosette.
Each time he is confronted by Javert, he has one more good deed to do. While his prior life was a selfish one, he ends up considering others above himself. He is a humble man, who, even as he faces death, asks God to forgive his trespasses, and take him home to Heaven.