He was a hugely prolific composer of Lutheran church music, especially motets, and assisted in bringing the stylistic innovations of the Venetian School north across the Alps into Germany.
Franck was able to make a living throughout this period as a musician, unlike his contemporary at Halle, Samuel Scheidt, who lost his Kapellmeister post.
Others are written in the polychoral style related to the Venetian practice, with the important difference that there is no spatial separation of the choirs: the antiphonal parts are all within the group.
Even though most of his motets use frankly Renaissance contrapuntal idiom, he often used the basso continuo, a relatively recent innovation of the early Baroque, and also used instrumental doublings of the vocal parts.
Franck was a conservative composer who was contemporary with the more famous, and much more progressive, Heinrich Schütz; however his works were popular and often reprinted during his lifetime.