Sassoon was born in Baghdad, where his father, Saleh Sassoon, was a wealthy businessman, chief treasurer to the pashas (the governors of Baghdad) from 1781 to 1817, and leader of the city's Jewish community.
The family were Sephardim with Spanish origins. His mother was Amam Gabbai. After a traditional education in the Hebrew language, Sassoon married Hannah in 1818. They had two sons and two daughters before she died in 1826. Two years later he married Farha Hyeem (who was born in 1812 and died in 1886). The pair had six sons and three daughters.
Following increasing persecution of Baghdad's Jews by Daud Pasha, the family moved to Bombay via Persia. Sassoon was in business in Bombay no later than 1832, originally acting as a middleman between British textile firms and Gulf commodities merchants, then investing in valuable harbour properties. His major competitors were Parsis, whose profits were built on their domination of the Sino-Indian opium trade since the 1820s.
When the Treaty of Nanking opened up China to British traders, Sassoon developed his textile operations into a profitable triangular trade: Indian yarn and opium were carried to China, where he bought goods which were sold in Britain, where he obtained Lancashire cotton products. He sent his son Elias David Sassoon to Canton, where he was the first Jewish trader (with 24 Parsi rivals). In 1845 David Sassoon & Sons opened an office in what would soon become Shanghai's British concession, and it became the firm's second hub of operations.
It was not until the 1860s that the Sassoons were able to lead the Baghdadi Jewish community in overtaking Parsi dominance. A particular opportunity was the American Civil War, during which turmoil American cotton exports declined. Lancashire factories replaced American cotton imports with Sassoon's Indian cotton.
From the China trade of those days David sassoon with the others Parsi Businessmans like Jamshedji Jejaboy continued this trade with China and from what ever wealth they earned here he started his own busienss of oil and start with the first Mill named E.D. Sassoon Mills he gained so Much Proesperity that Later Sassoons had been the largest mill owners and were known as Badshah of business of Bombay they overall had 17 Mills. Each Mill had around 15 to 20,000 workers. Later David Sassoon also entered the Large Scale Industries like in Cotton,Fabrics and various other sections
David Sassoon as being from the Orthodox Jewish Family Had cotninued his Jewish religious life even in his busy life he builds one of largest and the most beautiful synaguage of India Magen David synaguage of Byculla mumbaiand Ohel David Synaguage of Pune which are today's wellknown synaguages as a tourist attract points and is the part of th heitage and the cultural points of India He as other Jews observed Shabbth (Saturday off)and builds builds various charity trust named after him and his other family this organisation runs out of his total Private expense and does still exist, David Sassoon has an equal status like other Great people of Bombay who builds so many Greatest monuments,educational Institutions,great buildings and most prominent places of Bombay and pune
While the building of Gateway of India at Bombay by the British government on the first visit of the queen Victoria and King Albert Mr David Sassoon was the Donated 10 lakhs out of 25 Lakhs of total Amount of Construction on this David Sassoon was Awarded the true citizen and also the member of Legislative essembly of those days, David Sassoon Constructed the Sassoon Dock at Colaba Bombay the one of the largest port land the Docks ever here in Mumbai,David Sassoon Lived with his Family at Bycullas Bungloo which was also actually a Palace named shin Sangoo it is said once on the personal Invitation given by the Sassoons to Queen Victoria she Lived with them at their reidence this Bangloo was Later Donated to the Parsi Trust and is today's Massina Hospital, Near by the Victoria Garden (Rani Baugh of today's days) was also officially the properly of sassons which was donated to the Bombay municial corporation with the Construction of the Albert museam which was Build by the prominent Arcitect of those days and the inside view is totally similar like the Magen David synagogue of Mumbai and ohel David synagoague of pune and ALso has a famous Clock tower still known as Vicria tower is still kept there
Although David Sassoon did not speak English, he became a naturalised British citizen in 1853. He kept the dress and manners of the Baghdadi Jews, but allowed his sons to adopt English manners. His son, Abdullah changed his name to Albert, moved to England, became a Baronet and married into the Rothschild family. All the Sassoons of Europe are said to be descendants of David Sassoon.
He built a synagogue in the Fort (area) and another in Byculla, as well as a school, a Mechanics' Institute, a library and a convalescent home in Pune. David Sassoon was conscious of his role as a leader of the Jewish community in Bombay. He helped to arouse a sense of Jewish identity amongst the Bene Israeli and Cochin Jewish communities. The Sassoon Docks (built by his son) and the David Sassoon Library are named after him.
David Sassoon died in his country house in Pune in 1864. His business interests were inherited by his son Sir Albert Sassoon; Elias David had established a rival firm.