Droysen was born at Treptow in Pomerania (now Trzebiatów in Poland) on 6 July 1808. His father, Johann Christoph Droysen, was an army chaplain who had been present at the celebrated siege of Kolberg in 1806–1807. As a child, Droysen witnessed some of the military operations during the War of Liberation, his father by then being pastor at Greifenhagen, in the immediate neighbourhood of Stettin, which was held by the French for most of 1813. These youthful impressions laid the foundation of his ardent attachment to the Kingdom of Prussia. He was educated at the gymnasium of Stettin and at the University of Berlin; from 1827 to 1829 he was the private tutor of Felix Mendelssohn, who set several of his poems in his Op. 9 "12 Songs". In 1829 he became a master at the Graues Kloster, one of the oldest schools in Berlin; in addition, he gave lectures at the University of Berlin, from 1833 as "Privatdozent", and from 1835 as professor, without a salary. The famed historian Jacob Burckhardt visited his class in his last semester (1839–40).