In 1825 he was named sub-inspector of fine arts and a few months later married Amelia Syvoct, niece and adopted daughter of the celebrated Mme Récamier.
He visited Italy, Belgium, and the Netherlands, and accompanied Jean-François Champollion to Egypt in July 1828, where he devoted himself to the study of architectural works.
On returning from this second visit to the East, Lenormant continued his lectures at the Sorbonne, making a particular study of Christian civilization in its sources.
In 1846, the students of the Sorbonne, in retaliation for his part in the suppression of Edgar Quinet's chair, compelled Lenormant to give up his professorship; he was then given the editorship of the Correspondent, which be resigned in 1855.
In 1848 he was named director of the commission of historical monuments, and in 1849 an almost unanimous vote of the members of the Academy appointed him to the chair of archaeology in the Collège de France.