At a young age, Lasaulx became fascinated with classical philosophy. He studied at Bonn (1824-30) and then at Munich, where he focused on Schelling, Görres, and Baader, whose daughter he later married. After finishing his studies at the university, he spent the next four years traveling around Austria, Italy, Greece, and Palestine; visiting all the most important places from history. His trip to Athens was made as part of the party of Prince Otto of Wittelsbach, who had just been made King of the Hellenes
Returning to Germany, he received his doctorate from Kiel in 1835 with the dissertation "De mortis dominatu in veteres, commentatio theologica-philosophica", and was subsequently appointed to be docent of classical philology at the University of Wurzburg. It was about this time he married Julie Baader, Franz Baader's daughter.
On November 20, 1837, Clemens August, Archbishop of Cologne, was arrested and imprisoned by the Prussian government. This sent a shock through Catholic circles throughout Germany, and inspired both Lasaulx and his uncle to write pamphlets. His, Kritische Bemerkungen über die Kölner Sache (Critical Remarks about the Cologne Matter), was a controversial attack on the Prussians in general and diplomat Josias von Bunsen in particular.
Although the Wurzburg government tried to keep him there, Lasaulx left in 1844 to become Professor of Philology and Aesthetics at the University of Munich, where he became known for his magnetic style. He became involved in political matters, which resulted in the dissmissal of Minister Abel in 1847, this made heads of the University happy, but Ludwig I quite upset. He dismissed Lasaulx from his post, and upon protests by the students, and eight other professors as well. Lasaulx and three other former Munich lecturers were elected to the national assembly in Frankfort, where he identified himself with the conservatives.
In 1848 Ludwig I was forced to abdicate over a scandal involving his mistress Lola Montez. His successor, Maximilian II gave into pressure and reinstated Lasaulx and the others to their old posts in 1849. Later that year, Lasaulx was appointed to the Bavarian Chamber of Deptuties. He served there until his death on May 9, 1861.