Until the Sengoku period, peasants accounted for the majority of daimyō armies, so they accounted for the majority of ronin.

Especially in the Sengoku period, daimyō needed additional fighting men, and even if a master had perished, his rōnin was able to serve new lords. In contrast to the later Edo period, the bond between the lord and the vassal was loose, and some vassals who were dissatisfied with their treatment left their masters and sought new lords. Many warriors served a succession of masters, and some even became daimyō. As an example, Tōdō Takatora served ten lords. Additionally, the division of the population into classes had not yet taken place, so it was possible to change one's occupation from warrior to merchant or farmer, or the reverse. Saitō Dōsan was one merchant who rose through the warrior ranks to become a daimyō.

As Toyotomi Hideyoshi unified progressively more significant parts of the country, daimyō found it unnecessary to recruit new soldiers. The Battle of Sekigahara in 1600 resulted in the confiscation or reduction of the fiefs of large numbers of daimyō on the losing side; consequently, many samurai became rōnin. As many as a hundred thousand rōnin joined forces with Toyotomi Hideyori and fought at the Siege of Osaka. In the ensuing years of peace, there was less need to maintain expensive standing armies, and many surviving rōnin turned to farms or became townspeople. A few, such as Yamada Nagamasa, sought adventure overseas as mercenaries. Still, the majority lived in poverty as rōnin. Their number approached half a million under the third Tokugawa shōgun Iemitsu.

Initially, the shogunate viewed them as dangerous and banished them from the cities or restricted the quarters where they could live. They also prohibited serving new masters. As rōnin found fewer options, they joined in the Keian Uprising 1651. This forced the shogunate to rethink its policy. It relaxed restrictions on daimyō inheritance, resulting in fewer confiscations of fiefs, and it permitted rōnin to join new masters.

Not having the status or power of employed samurai, rōnin were often disreputable and festive,[13] the group targeted humiliation or satire. It was undesirable to be a rōnin, as it meant being without a stipend or land. As an indication of the shame felt by samurai who became rōnin, Lord Redesdale recorded that a rōnin killed himself at the graves of the forty-seven rōnin. He left a note saying that he had tried to enter the service of the daimyō of Chōshū Domain but was refused. He killed himself, wanting to serve no other master and hating being a rōnin. On the other hand, the famous 18th-century writer Kyokutei Bakin renounced his allegiance to Matsudaira Nobunari, in whose service Bakin's samurai father had spent his life. Bakin voluntarily became a rōnin, and eventually spent his time writing books (many of them about samurai) and engaging in festivities.

In the 19th century, Emperor Meiji abolished the Samurai class and the ronin died with them.

All but some.