Maritain was born in Paris, the son of Paul Maritain, who was a lawyer, and his wife Geneviève Favre, the daughter of Jules Favre, and was reared in a liberal Protestant milieu. He was sent to the Lycée Henri-IV. Later, he attended the Sorbonne, studying the natural sciences: chemistry, biology and physics.
At the Sorbonne, he met Raïssa Oumançoff, a Russian Jewish émigré. They married in 1904. A noted poet and mystic, she participated as his intellectual partner in his search for truth. Raissa's sister, Vera Oumançoff, lived with Jacques and Raissa for almost all their married life.
At the Sorbonne, Jacques and Raïssa soon became disenchanted with scientism, which could not, in their view, address the larger existential issues of life. In 1901, in light of this disillusionment, they made a pact to commit suicide together if they could not discover some deeper meaning to life within a year. They were spared from following through on this because, at the urging of Charles Péguy, they attended the lectures of Henri Bergson at the Collège de France. Bergson's critique of scientism dissolved their intellectual despair and instilled in them "the sense of the absolute." Then, through the influence of Léon Bloy, they converted to the Roman Catholic faith in 1906.
In the fall of 1907 the Maritains moved to Heidelberg, where Jacques studied biology under Hans Driesch. Hans Driesch’s theory of neo-vitalism attracted Jacques because of its affinity with Henri Bergson. During this time, Raïssa fell ill, and during her convalescence, their spiritual advisor, a Dominican friar named Fr. Humbert Clérissac, introduced her to the writings of Thomas Aquinas. She read them with enthusiasm and, in turn, exhorted her husband to examine the saint’s writings. In Thomas, Maritain found a number of insights and ideas that he had believed all along. He wrote:
"Thenceforth, in affirming to myself, without chicanery or diminution, the authentic value of the reality of our human instruments of knowledge, I was already a Thomist without knowing it...When several months later I came to the Summa Theologiae, I would construct no impediment to its luminous flood."
From the Angelic Doctor (the honorary title of Aquinas), he was led to "The Philosopher", as Aquinas called Aristotle. Still later, to further his intellectual development, he read the Neo-Thomists.
Beginning in 1912, Maritain taught at the Collège Stanislas. He later moved to the Institut Catholique de Paris. For the 1916–1917 academic year, he taught at the
Petit Séminaire de Versailles. In 1930 Maritain and Étienne Gilson received honorary doctorates in philosophy from the Pontifical University of Saint Thomas Aquinas, Angelicum. In 1933, he gave his first lectures in North America in Toronto at the Pontifical Institute of Mediaeval Studies. He also taught at Columbia University; at the Committee on Social Thought, University of Chicago; at the University of Notre Dame, and at Princeton University.
From 1945 to 1948, he was the French ambassador to the Holy See.
Afterwards, he returned to Princeton University where he achieved the "Elysian status" (as he put it) of a professor emeritus in 1956. Raissa Maritain died in 1960. After her death, Jacques published her journal under the title "Raissa's Journal." For several years Maritain was an honorary chairman of the Congress for Cultural Freedom, appearing as a keynote speaker at its 1960 conference in Berlin.
From 1961, Maritain lived with the Little Brothers of Jesus in Toulouse, France. He had an influence on the order since its foundation in 1933. He became a Little Brother in 1970.
Jacques and Raïssa Maritain are buried in the cemetery of Kolbsheim, a little French village in Alsace where he had spent many summers at the estate of his friends, Antoinette and Alexander Grunelius.
A cause for beatification of him and his wife Raissa is being planned.