In 1838 he entered the Würzburg seminary, went to the German College at Rome in 1841, was ordained priest in 1844, and the following year took a degree in theology.
In the generation after Johann Adam Mohler (d. 1838) and Döllinger (1799-1890) he carried on their methods and helped to establish what was the special character of the German school, exact investigation of the historical development of theology, rather than philosophical speculation about the corollaries of dogma.
The best-known and most useful is his Enchiridion symbolorum et definitionum (first ed., Würzburg, 1854), a handbook containing a collection of the chief decrees and definitions of councils, list of condemned propositions, etc., beginning with the oldest forms of the Apostles' Creed.
After Denzinger's death, Professor Ignaz Stahl continued the work of re-editing the Enchiridion with additional decrees of Leo XIII.
The latest editions have added doctrinal statements of the second half of the twentieth century, including the teachings of the Second Vatican Council and recent Popes.