Osterwald studied at the Gymnasium in Salzwedel and the Franeschen Stiftungen in Halle. He studied Philology at the University in Halle and later active as a teacher at the Königlichen Pädigogium in Halle and at the Domgymnasium in Merseburg.
In 1865 he became headmaster of the Gymnasium in Mühlhausen. During his period in Mühlhausen, he published many pedagogical writings and poems. Around 70 of his nature, travel, and love poems were set to music by composer Robert Franz.
In 1889, his former student Richard von Hertwig pressed for the erection of a monument in his memory in the Mühlhäuser Stadtwald.
Osterwald, together with the cathedral organist Engel in Merseburg, prepared an edition of the Geistlichen Lieder of Johann Frank, providing new texts. Osterwald also wrote his own church songs.
Osterward received the House Order of Hohenzollern.
