De Lagarde was born in Berlin as Paul Bötticher. In early adulthood he legally adopted the family name of his maternal line out of respect for his great-aunt who raised him.
At [[Humboldt University of Berlin]] (1844–1846) and [[University of Halle-Wittenberg]] (1846–1847) he studied [[theology]], [[philosophy]] and [[Semitic languages|Oriental languages]]. In 1852 his studies took him to London and Paris.<ref>{{cite EB1911|wstitle=Lagarde, Paul Anton de|last=|first=|page=}}</ref> In 1852, he received a 1,000 [[thaler]] grant from [[Frederick William IV of Prussia|King Frederick William IV]] to study abroad. He traveled to London to work at the [[British Museum]].<ref name=LagardeA/>{{rp|19–20}} In January 1853, Lagarde traveled to Paris to work in the [[Bibliothèque nationale de France|Bibliothèque nationale]]. He relied on [[Ernest Renan]] to check out manuscripts for him.<ref name=LagardeA/>{{rp|32}}
Lagarde's death in 1891 shocked friends who did not know he was ill. HisThree years alter, his wife Anna wrotepublished many of his letters in a biographymemoir of her husband in 1894.<ref name=LagardeA>Lagarde, Anna de. ''[https://www.google.com/books/edition/Paul_de_Lagarde/iZEEAAAAYAAJ?hl=en&gbpv=1&pg=PA1&printsec=frontcover Paul de Lagarde: Erinnerungen aus seinem Leben für die freunde Zusammengestellt]''. Germany, W. F. Kaestner, 1894. 1.</ref>{{rp|1}}
