The Mafia had eventually expanded to twenty-six crime families nationwide in the major cities of the United States, with the center of organized crime based in New York and its surrounding areas. After many turf wars, the Five Families ended up dominating New York, named after prominent early members: the Bonanno family, the Colombo family, the Gambino family, the Genovese family, and the Lucchese family. These families held underground conferences with other mafia notables like Joe Porrello from Cleveland, and other gang leaders, such as Al Capone.
Boss—The head of the family, usually reigning as a dictator, sometimes called the don or "godfather". The Boss receives a cut of every operation taken on by every member of his family. Depending on the family, the Boss may be chosen by a vote from the Caporegimes of the family. In the event of a tie, the Underboss(es) must vote. In the past, all the members of a family voted on the Boss, but by the late 1950s, any gathering such as that usually attracted too much attention.
Underboss—The Underboss, usually appointed by the Boss, is the second in command of the family. The Underboss is in charge of all of the Capos, who are controlled by the Boss. The Underboss is usually first in line to become Acting Boss if the Boss is imprisoned or dies. There are normally no more than two or three Underbosses in a family, if there's more than one at all.
Consigliere—The Consigliere is an advisor to the family and sometimes seen as the Boss's "right-hand man". They are often low profile gangsters that can be trusted. They are used as a mediator of disputes or representatives or aides in meetings with other families. They often keep the family looking as legitimate as possible and are sometimes, themselves, legitimate apart from some minor gambling or loan sharking. Some do not have crews of their own, but still wield great power in the family. They are also often the liaison between the Don and important 'bought' figures, such as politicians or Judges.
Caporegime (or Capo)—A Capo (sometimes called a Captain) is in charge of a crew. There are usually four to six crews in each family, possibly even seven to nine crews, each one consisting of up to ten Soldiers. Capos run their own small family but must follow the limitations and guidelines created by the Boss, as well as pay him his cut of their profits. Capos are nominated by the Underboss, but typically chosen by the Boss himself.
Soldier—Soldiers are members of the family, and can only be of Italian background (although a few families, including the Gambinos, require men to be of only half Italian descent on their father's side). Soldiers start as Associates that have proven themselves. When the books are open, meaning that there is an open spot in the family, a Capo (or several Capos) may recommend an up-and-coming Associate to be a new member. In the case that there is only one slot and multiple recommendations, the Boss will decide. The new member usually becomes part of the Capo's crew that recommended him. Some soldiers work by themselves, earning money for the Family alone though most are part of crews. Sometimes a soldier will be called a button man, because, in theory, when a capo presses a button, someone dies. They are also called made men, who have made their bones, by committing a murder in front of Mafia witnesses or committed a murder by orders from a high member of the family (a Capo, an Underboss, a Consigliere or Boss). This ensures the soldier's reliability: he will never testify against a man who could testify against him. Being made is the beginning but not the end of a Mafia career. (The definitions of made man and making one's bones are inferred: Most books on the Mafia—fiction or nonfiction—assume these terms but never define them.)
Associate—An Associate is not a member of the mob, and an Associate's role is more similar to that of an errand boy. They are usually a go-between or sometimes deal in drugs to keep the heat off the actual members, or they are people the family does business with (restaurant owners, etc.). In other cases, an associate might be a corrupt labor union delegate or businessman. Non-Italians will never go any further than this. However, occasionally an associate will become powerful within his own family, for example Joe Watts, a close associate of John Gotti.
The American Mafia's organizational structure and system of control were created by Salvatore Maranzano (who became the first "capo di tutti capi" in the US, though he was killed after holding the position for only six months, by Lucky Luciano).
Most recently there have been two new positions in the family leadership: the family messenger and Street Boss. These positions were created by former Genovese leader Vincent Gigante.
Each faction was headed by a caporegime, who reported to the boss. When the boss made a decision, he never issued orders directly to the soldiers who would carry it out, but instead passed instructions down through the chain of command. In this way, the higher levels of the organization were effectively insulated from incrimination if a lower level member should be captured by law enforcement. This structure is depicted in Mario Puzo's famous novel The Godfather. In The Godfather: Part II, These links are called "buffers": they provide what the intelligence community calls plausible deniability.