Zemurray's birth name was Schmuel Zmurri (Yiddish: שמואל זמורי, Russian: Шмуэль Давидович Змура, Shmuel Davidovich Zmura).

Zemurray worked many odd jobs during his youth, being a carpenter's assistant, delivery boy, traveling merchant, and housecleaner.

In Mobile, Zemurray specialized in buying cheap bananas in danger of being overripe and quickly transporting and selling them in the surrounding region by rail.

At this point, Hubbard believed that Cuyamel Fruit Company's debts had grown too large, and Zemurray bought his share of the business.

In spite of this instruction, Zemurray devised a plan to overthrow Honduran president Miguel Dávila in order to prevent the deal.

They sailed to Honduras in a former United States Navy vessel, where they began a war to install exiled Honduran former president Manuel Bonilla, who had been living in New Orleans.

Cuyamel Fruit began to cultivate crops beyond bananas: coconuts, pineapples, palm oil, cattle, lumber, and sugarcane.

[5] Though Zemurray had prided himself on independence, he sold his company because of increasing pressure from the Department of State and because of the financial insecurity brought on by the Great Depression in 1929.

[7] This encouraged Zemurray to return to the banana business by buying a controlling share of United Fruit and voting out the board of directors.

Zemurray then visited individual United Fruit shareholders and collected their proxies, which would enable him to gain control of the company.

He gained a detailed understanding of operations, resulting in mass terminations of weak employees, improved efficiency in the use of ships, and new financial approaches.

In 1953, the U.S. State Department and United Fruit embarked on a major public relations campaign to convince the American people and the rest of the U.S. government that Colonel Jacobo Arbenz intended to make Guatemala a Soviet "satellite".

Zemurray authorized Edward Bernays to launch a propaganda campaign against Col. Arbenz's democratically elected government, which intended to expropriate some of the unused land owned by the United Fruit Co. and redistribute it to the local peasants.

In 1954, the campaign succeeded and the U.S. Central Intelligence Agency helped orchestrate a coup that replaced Arbenz with a military junta led by Col. Carlos Castillo Armas.

Zemurray supported President Franklin D. Roosevelt's New Deal policies,[7] helping to draft the Agricultural Adjustment Administration industry codes, and contributed financially to left-wing causes, such as The Nation magazine.

In 1945, Zemurray and Coryell McKinney donated 25 acres (10 ha) of land in Hammond, Louisiana, for a memorial park to honor Samuel Jr. and his flight crew.

[12] Zemurray became a philanthropic and gave thousands of dollars to Tulane University, Radcliffe College, The Nation magazine, and to clinics and hospitals in New Orleans.