Genin are the lowest level of ninja and also the ones that display the most difference in power. When they become Genin, ninja start to do their bit for their village's economy – being sent on missions that the village gets paid for. They are typically sent either on D-Rank missions, which are almost entirely risk-free jobs of manual labor, or, very rarely, on C-Rank missions, which are a cut above that and begin to verge on real "ninja" work that have a very low possibility of risk to the ninja involved. When Konohagakure was shorthanded in upper-level ninja because of the attack by Otogakure and Sunagakure, the village had to occasionally send Genin on higher-ranked missions

Genin are put in four-man cells or squad, consisting of three Genin and a Jonin-sensei, in order to learn teamwork and experience true ninja life under the supervision and protection of an elite shinobi. The make-up of these teams is based on the individual skills of the Genin, so that there will be a balance between the teams. For instance, Naruto Uzumaki, who passed with the lowest grades, was put in a team with Sasuke Uchiha and Sakura Haruno, who passed with the highest grades and highest written exam scores, respectively. The teams are usually made up of two boys and one girl, though there are exceptions.

Due to the fact that Genin are the lowest level ninja, they normally provide limited use during dangerous missions (B-rank or higher), and are usually only capable of successfully completing E or D-rank techniques. However, it should be noted that Genin is simply a rank, and is not always an accurate representation of a ninja's skill level. Naruto Uzumaki is still a Genin, but regularly goes up against the S-Class criminals of Akatsuki.