The Sulu “sea world” has had a tempestuous history. Its people have been characterized by a fierce sense of cultural and political independence. The islanders were converted to the Muslim faith by the missionary adventurer Abu Bakr in the mid-15th century. He married a local princess, inherited the title of sultan, and turned his island principality into a regional Muslim state. The Spaniards never subdued the inhabitants, whom they called Moros (Moro); they were a fiercely independent people whose culture was a meeting ground for sea traders, shell and coral producers, fishermen, pirates, and slave traders. The Moros had extensive regional contacts and raided areas as far away as Malaysia and northern Luzon.

The Moros were subjugated after a series of U.S. campaigns (1899–1913), during which John J. Pershing (later commander in chief of the U.S. forces in World War I) first distinguished himself as an officer. The archipelago was treated as a separate unit under the U.S. administration, and civil government came into force in 1914. In March 1915 the reigning sultan abdicated his civil powers, retaining only his rights as head of the Islamic faith, but sporadic fighting continued between government forces and outlaw bands. In 1940 the sultan ceded the Sulus to the Philippines, but as recently as 1962 he claimed sovereignty over the Malaysian state of Sabah (northern Borneo).

Resistance to civil authority has continued in the form of illegal trade and piracy. The islands, with their myriad coves and hidden passages, are a haven for smugglers, who transport goods in small craft from Sabah to Luzon and Mindanao.

The Sulu islands' culture is primarily one of the sea; only Jolo has a significant agricultural economy. There are several pearl beds in the group, and marine resources include button shell, mother-of-pearl, coral, shark fins, bêche-de-mer (sea cucumbers), turtle shells, turtle eggs, and sponges. The Turtle Islands in the west are the centre of turtle fisheries. This marine wealth has not been tapped on an organized basis and remains a subsistence economic activity, usually supplemented by small-scale agriculture. Rice must be imported. There are no significant mineral resources, and forestry is not developed.

The largest ethnic groups are the Tau Sug, who live on the coast in pile-built villages, and the Samal, who formerly lived on boats or chose a shoreline environment but who have increasingly settled inland. The largest settlements are Jolo (the chief port), Siasi, Sitangkai, and Talipaw (Jolo island). Pop. (2000) 941,985.