Who was the first Straw Hat to join after Luffy?

Luffy decides to recruit Zoro despite his bad reputation and imprisonment.

Ch. 3 Suggest an edit Report

Luffy approaches the bound Zoro and offers him a place in his pirate crew.

Ch. 3, p. 15 Suggest an edit Report

Zoro accepts Luffy's offer and joins the crew after being freed.

Ch. 6 Suggest an edit Report