Becoming a Shichibukai
A pirate may choose to join the Shichibukai if a space becomes vacant (which means that at least one Shichibukai must resign or be expelled from the group, the former being Jinbe's case and the latter being Crocodile's case). However, in order for one to become a Shichibukai once this position opens up, one must be able to exhibit their strength against other pirates[3] while choosing to pledge loyalty to the World Government (this ironically encourages pirates to gain infamy to become a Shichibukai) by making a pact with the Gorosei. If the pirate in question can be used as intimidation, the position may be offered to them, if no other pirate has accepted the position or proven to be more of an asset to the World Government. As expected, most members were already notorious pirates with high bounties, but even relatively unknown pirates can be admitted if they accomplish a feat to prove their strength. Blackbeard's victory over Portgas D. Ace and Trafalgar Law obtaining and sending the hearts of 100 pirates to Marine Headquarters are the examples.
