Dedicated from childhood to the church, Johannes Oertel began in his thirteenth year to study with a Lutheran clergyman, expecting to become a foreign missionary. He revealed such talent for drawing, however, that his preceptor urged him to study art. Accordingly, he became the pupil of J. M. Enzing-Müller, an engraver, with whom he spent some time in Munich, where he was much influenced by the painting of Wilhelm von Kaulbach. In 1902, he received at the hands of Bishop Gailor the degree of D. D.
In 1848 he came to the United States and settled at Newark, New Jersey, where he was soon joined by his parents and two brothers. Here he gave lessons in drawing. Oertel made sketches for a series of four great paintings which should illustrate the redemption of mankind. Thereafter he looked upon the completion of these pictures as the major purpose of his life, and most of his work, during more than fifty years of moving from place to place, was undertaken in an effort to secure means for accomplishing it. From 1852 to 1857 he made steel-engravings for banknotes, painted portraits, and even colored photographs. In 1857-58 he designed the decorations for the ceiling of the House of Representatives in the Capitol at Washington; a few months of 1862 he spent with the Army of the Potomac, gathering material for several war paintings. In the sixties, at Westerly, he painted a picture first called "Saved, or an Emblematic Representation of Christian Faith, " which came to be widely known in chromo reproductions under the title "Rock of Ages. " An amazing number of photographs and lithographs after the original were sold, bringing to the publisher a handsome income in royalties, but through a flaw in the copyright, the artist was deprived of all profits after the first few years. He had been confirmed in the Protestant Episcopal Church in 1852 and at Westerly occasionally acted as lay reader.
In 1867, upon the urging of his rector, he was admitted to deacon's orders by Bishop T. M. Clark. Two years later he moved to Lenoir, North Carolina, where he assumed charge of a rural church and two mission stations - being ordained priest in 1871 - and founded a school for girls. Here he remained until 1876. Later he was rector of another church at Morganton, North Carolina, for eighteen months; and after a year in Florida he lived for various periods at Washington, D. C. , Sewanee and Nashville, Tenneessee, and St. Louis, Missouri, where in 1889-91 he was instructor in fine arts at Washington University. He always looked upon religious art as his chief vocation, however, and his paintings and ecclesiastical wood carving were his principal means of support. The former are to be seen in churches in New York, Glen Cove, Lenoir, St. Louis, Jackson, Emmorton and Belair, and Washington, D. C. , in many instances accompanied by elaborate wood carvings from his hand. An especially notable work was his altar and reredos for the Church of the Incarnation, Washington. For a while he took charge of the church at Emmorton, Maryland, during the illness of its rector, his friend.
In 1895, his sons having relieved him of the necessity for gaining a livelihood, Oertel began at last to paint the first picture in his "Redemption" series: "The Dispensations of Promise and the Law. " This was followed by "The Redeemer, " "The Dispensation of the Holy Spirit, " and "The Consummation of Redemption. " The last of the four was completed in 1902. In 1897 he had declined an offer of $10, 000 for the first painting, because he was unwilling to break the series, which he ultimately gave to the University of the South. There, in 1902, he received at the hands of Bishop Gailor the degree of D. D. Thenceforth he lived with a son at Vienna, Virginia, where he painted prolifically in his characteristic vein until the end. In 1906-07 he produced the paintings and designed the woodwork for the reredos of the Cathedral at Quincy, Illinois. He died at Vienna at the age of eighty-six.
Oertel's draftsmanship was excellent from the beginning. At the outset of his painting career his delineation of form was far superior to his use of color; frequently his canvases were done in monochrome. In his later years, however, notably in the "Redemption" series and in the work for the Cathedral at Quincy, he used color with striking results. Always having a didactic purpose, his pictures sometimes include symbolic detail at the cost of artistic effect. Nevertheless, his composition is forceful and his rendering of the human figure and of animals thoroughly able.
The University of the South has a number of his works besides the "Redemption" series; "The Walk to Gethsemane" is in the National Gallery at Washington; "It is Finished, " "The Church Militant, " and "The Burial of Moses" are at Washington Cathedral.
Johannes Oertel married Julia Adelaide Torrey in 1851. She became the mother of four children, and until her death in 1907 was the "balance wheel" of her husband's life.