He studied theology and philology at Heidelberg and later at Halle under Hermann Hupfeld, who persuaded him to include Arabic, Syriac and Egyptian.
In 1854 he was appointed garrison-preacher at Mannheim for the Evangelical Church in Baden; and in 1858 he was licensed to lecture at Heidelberg, where in 1861 he was made professor extraordinarius.
[citation needed] Throughout his life he followed Hupfeld's plan in his scientific treatment of the Old Testament—that of reconciling the results of a free criticism with a belief in divine revelations.
His practical experience of pastoral work also proved of service to him when he became a professor of theology, for if there is one quality more striking than another in the writings of Riehm, it is that of sympathy with orthodox believers (TK Cheyne).
In 1865 Riehm was made a member of the commission for the revision of Luther's translation of the Bible, and became one of the editors of the quarterly review, Theologische Studien und Kritiken.