Shortly after returning from service in the Morea expedition he took part in the July Revolution, and in 1832 was sent to Algeria, at the start of the French invasion, where he served with distinction for the next 16 years.

He started his political career following the French Revolution of 1848 and the establishment of the Second Republic, being elected member of the National Assembly, and soon became one of the leaders of the Moderate Republicans.

As Minister of War in the French provisional government, Cavaignac was tasked with putting down the June Days uprising, a revolt by Parisian workers against the National Assembly, and for this was temporarily given emergency powers.

[1] At the time of his birth, his father was the mayor of Saint-Sauveur, and previously during the French Revolution had been a Jacobin member of the National Convention, where he voted for the execution of Louis XVI.

[5] He was promoted to lieutenant-colonel in June 1840, to colonel in August 1841,[1] and to maréchal de camp in 1844, the latter on the request of Henri d'Orléans, Duke of Aumale himself, son of King Louis Philippe.

About a month later, Cavaignac returned to France to take his seat as a representative of Lot to the constituent National Assembly, after being the most voted in that department on the 1848 legislative election.

At the National Assembly he sat among the Moderate Republicans, and there, at the 10 June session, he engaged in a debate with the Bonapartist deputy Georges-Charles de Heeckeren d'Anthès, which started a lasting antagonism between the general and Louis-Napoléon Bonaparte.

By 24 June, the insurgents posed such a threat that the National Assembly gave Cavaignac dictatorial powers, and disbanded the Executive Committee.

[8] Cavaignac viewed the insurrection as a military issue above all else, and thus relied on the regular army with assistance from the National Guard,[8] and did not hesitate to use cannons to break through barricades.

At the time Alphonse de Lamartine even suspected Cavaignac of having deliberately chosen to delay the government's response, allowing the early protests on 23 June to grow, so that his ultimate victory over the insurgents would be more decisive.

As a committed Republican, Cavaignac strove as head of state of France to secure the democratic institutions recently achieved with the February Revolution,[7] and selected the members of his cabinet accordingly.

In his early government, Cavaignac imposed control over political clubs[7] and suppressed the left-wing press, which he deemed responsible for inciting the armed insurrection of June.

[11] Direct relief was provided by the government to supplant the national workshops, and large-scale public works were undertaken in order to reduce unemployment.

After the Austrian victory in late July at the Battle of Custoza, Cavaignac organized an army to support Piedmont-Sardinia, but in the absence of a request did not intervene.

In contradiction, he also organized, and later cancelled, in November an expeditionary force to rescue Pope Pius IX, who had fled from a republican revolution in Rome.

With that goal, Cavaignac in October introduced two Orleanists into his cabinet (Vivien and Dufaure) when chance appeared for a ministerial reform, and even indirectly approached Adolphe Thiers, leader of the party, with a proposal for the vice-presidency in his government.

[27] As the first results to come in already suggested an imminent victory for Louis-Napoléon, Cavaignac was reportedly urged by his adviser Colonel Charras to carry out a self coup to remain in power, but he refused.

In a brief farewell speech, Cavaignac thanked the parliament for “its confidence and its kindness toward me" and presented the resignation of himself and his cabinet, then proceeded to return to his seat as a member of the Assembly.

[31] The anti-suffrage law of 31 May was approved, and revoking it was used as a pretext by Louis-Napoléon for his coup d'état of 2 December 1851, in which he seized dictatorial powers and dissolved the National Assembly.

His funeral was held in Paris and had as pallbearers his former colleagues Michel Goudchaux, Joseph Guinard, Jules Bastide, and a worker named Bayard.