The young La Rochejacquelein entered the military academy at Saint-Cyr at the age of sixteen and in 1823 he received a commission as second lieutenant in the cavalry.
In 1825 he had been made a peer, but he resigned shortly after the Revolution of 1830, which brought the younger branch of the House of Bourbon to the throne of France.
He took his seat among the members of the Extreme Right, or Legitimist party, with whom he usually cast his vote, although he occasionally support liberal measures.
In 1848 the "Gazette de France" supported his candidacy for the presidency of the newly established French Republic, but he obtained only an insignificant number of votes.
In the senate La Rochejacquelein always showed himself an ardent defender of Catholicism, but he may be reproached with having given his support to the whole foreign policy of the imperial Government.