The Chumash were among the first native Californians to be encountered by the Spanish-sponsored explorer Juan Rodríguez Cabrillo (Cabrillo, Juan Rodríguez) (1542–43). At the time of colonization, the Spanish named the major Chumash groups the Obispeño, Purismeño, Ynezeño, Barbareño, and Ventureño (for the Franciscan missions San Luis Obispo de Tolosa, La Purísima Concepción, Santa Ynez, Santa Barbara, and San Buenaventura, respectively), the inland Emigdiano and Cuyama, and the Isleño.

Traditionally, the majority of the Chumash population lived along the seashores and relied for food largely on fish, mollusks, and sea mammals and birds. They also collected a number of wild plant foods; most important among these were acorns, which the Chumash detoxified using a leaching process. Their houses were dome-shaped and large; normally each served several families and had several rooms. Villages formed the basis of Chumash political and social organization. The Chumash were skilled artisans: they made a variety of tools out of wood, whalebone, and other materials, fashioned vessels of soapstone, and produced some of the most complex basketry in native North America. The Chumash were also purveyors of clamshell-bead currency for southern California.

Early 21st-century population estimates indicated some 7,000 Chumash descendants.