Blanqui was born in Puget-Théniers, Alpes-Maritimes, where his father, Jean Dominique Blanqui, of Italian descent, was subprefect. He was the younger brother of the liberal economist Jérôme-Adolphe Blanqui. He studied both law and medicine, but found his real vocation in politics, and quickly became a champion of the most advanced opinions. A member of the Carbonari society since 1824, he took an active part in most republican conspiracies during this period. In 1827, under the reign of Charles X (1824–1830), he participated in a street fight in Rue Saint-Denis, during which he was seriously injured. In 1829, he joined Pierre Leroux's Globe newspaper before taking part in the July Revolution of 1830. He then joined the Amis du Peuple ("Friends of the People") society, where he made acquaintances with Philippe Buonarroti, Raspail, and Armand Barbès. He was condemned to repeated terms of imprisonment for maintaining the doctrine of republicanism during the reign of Louis Philippe (1830–1848). In May 1839, a Blanquist inspired uprising took place in Paris, in which the League of the Just, forerunners of Karl Marx's Communist League, participated.
He was released during the revolution of 1848, only to resume his attacks on existing institutions. The revolution had not satisfied him. The violence of the Société républicaine centrale, which was founded by Blanqui to demand a change of government, brought him into conflict with the more moderate Republicans, and in 1849 he was sentenced to ten years' imprisonment. While in prison, he sent a brief address (written in the Prison of Belle-Ile-en-Mer, 10 February 1851) to a committee of social democrats in London. The text of the address was noted and introduced by Karl Marx.
In 1865, while serving a further term of imprisonment under the Empire, he escaped, and continued his propaganda campaign against the government from abroad, until the general amnesty of 1869 enabled him to return to France. Blanqui's predilection for violence was illustrated in 1870 by two unsuccessful armed demonstrations: one on 12 January at the funeral of Victor Noir, the journalist shot by Pierre Bonaparte; the other on 14 August, when he led an attempt to seize some guns from a barracks. Upon the fall of the Empire, through the revolution of 4 September, Blanqui established the club and journal La patrie en danger.
He was one of the group that briefly seized the reins of power on 31 October and for his share in that outbreak he was again condemned to death in absentia on 9 March of the following year. On 17 March, Adolphe Thiers, aware of the threat represented by Blanqui, took advantage of his resting at a friend physician's place, in Bretenoux in Lot, and had him arrested. A few days afterwards the insurrection which established the Paris Commune broke out, and Blanqui was elected president of the insurgent commune. The Communards offered to release all of their prisoners if the Thiers government released Blanqui, but their offer was met with refusal, and Blanqui was thus prevented from taking an active part. Karl Marx would later be convinced that Blanqui was the leader that was missed by the Commune. Nevertheless, in 1872 he was condemned along with the other members of the Commune to transportation; on account of his broken health this sentence was again commuted to one of imprisonment. On 20 April 1879 he was elected a deputy for Bordeaux; although the election was pronounced invalid, Blanqui was freed, and immediately resumed his work of agitation.