Mike Hoare, an Irish soldier of fortune who led white mercenary forces in civil wars in Congo in the 1960s and a ragtag band of commandos in a farcical aborted coup in the Seychelles in 1981, died on Sunday in Durban, South Africa. He was 100.

His son Chris confirmed the death, in a nursing home.

Mr. Hoare crossed seas on a sailboat and Africa (south to north) on a motorcycle. He searched for the fabled lost city of the Kalahari and retraced the steps of Victorian explorers to the sources of the Nile. He fought the Japanese in Burma in World War II, rescued hostages from rebel forces in Congo, found nuns and priests hacked to death in the bush and was imprisoned in South Africa for hijacking an airliner.

The exploits of Mr. Hoare, who was called “Mad Mike” for his recklessness under fire, were recounted in books by him and others, in a film starring Richard Burton, and in sheaves of foreign correspondents’ dispatches, now faded yellow in old newspaper morgues with datelines from far-off places.

Tiring of life as an explorer and safari guide, Mr. Hoare first hired out as a mercenary in 1960-61, leading a European force fighting for Moise Tshombe, whose Katanga province was trying to break away from the newly independent Republic of Congo.