The interior is divided vertically into three sections, which increase in brightness from the bottom upwards. The lowermost portion of the benches for the church visitors is kept relatively dark and in the design symbolizes the suffering of the world. The second section, located above, is kept white and blue, and reserved for the emperor. The uppermost portion of the indirect and hidden illuminated ceiling painting is dedicated to God and eternity.
The ceiling fresco "Life of Saint Nepomuk" is considered one of the masterpieces by Cosmas Damian Asam. The high altar of the Asam Church is framed by four spiral columns. At the high altar, these four columns are used as a reference to the four-Bernini columns over the grave of St. Peter in St. Peter's in Rome. At the top is God, the Saviour. Below the tabernacle, a relic of John of Nepomuk is kept. Two angels, sculpted by Ignaz Günther, flank the gallery altar and were added at a later date.
Compared to a usually very strictly divided baroque churche the Asamkirche has shows some peculiarities due to its status as a private chapel: The church altar is situated in the west, not the east as usual. In addition, the crucifix opposite the pulpit was hung too low. In Baroque churches it was to hang above the pulpit, so that the preacher had to look up to Jesus Christ.