Ewald was born at Göttingen where his father was a linen weaver. In 1815 he was sent to the gymnasium, and in 1820 he entered the University of Göttingen, where he studied with J.G. Eichhorn and T. C. Tychsen, specialising in oriental languages. At the close of his academic studies in 1823 he was appointed to a mastership in the gymnasium at Wolfenbüttel, and made a study of the oriental manuscripts in the Wolfenbüttel library. But in the spring of 1824 he was recalled to Göttingen as theological tutor (), and in 1827 (the year of Eichhorn's death) he became professor extraordinarius in philosophy and lecturer in Old Testament exegesis. Heinrich Ewald married in 1830 Wilhelmina (1808–1846), daughter of C.F. Gauss. Of all of Gauss' children, Wilhelmina was said to have come closest to her father's talent, but she died young. In 1831 Heinrich Ewald was promoted to professor ordinarius in philosophy; in 1833 he became a member of the Royal Scientific Society, and in 1835, after Tychsen's death, he entered the faculty of theology, taking the chair of Oriental languages.