He studied at the Lycée Janson de Sailly. He holds engineering degrees from the École Polytechnique (class of 1946) and Supaéro (class of 1951). In 1963, he received an EMBA from HEC Paris.
Dassault married Nicole Raffel on 5 July 1950. They have four children: Olivier, Laurent, Thierry, and Marie-Hélène.
Serge Dassault is the son of Marcel Dassault, from whom he inherited the Dassault Group, and Madeline Dassault (née Minckes). Both his parents are of Jewish heritage but later converted to Roman Catholicism. Since the elder Dassault's death in 1986, Serge Dassault has continued developing the company, with the help of CEOs Charles Edelstenne and Éric Trappier.
In 2004, he became a senator, and in this position, he has been an outspoken advocate of conservative positions on economic and employment issues, claiming that France's taxes and workforce regulations ruin its entrepreneurs. In November 2012, responding to the Ayrault government's plan to legalise gay marriage, he controversially said, during an interview for France Culture, that authorising gay marriage cause "no more renewal of the population. [...] We'll have a country of homosexuals. And so in ten years there'll be nobody left. It's stupid".
He is a member of the Union for a Popular Movement political party, as is his son Olivier, who is a deputy in the French National Assembly. He is a former mayor of the city of Corbeil-Essonnes, a southern suburb of Paris. In 2005, he inaugurated the 2 million euros Islamic cultural centre (comprising a mosque) in his city of Corbeil-Essonnes. In December 1998, he was sentenced to two years' probation in the Belgian Agusta scandal, and was fined 60,000 Belgian francs (about €1,500).
According to Forbes, Dassault's net worth was estimated in 2016 at US$15 billion.