He studied at the Royal Danish Academy of Fine Arts where he won the small gold medal in 1767 and the large gold medal in 1768 with a project for a royal military academy.

The large gold medal qualified him for the first vacant travel stipend.

He worked for Caspar Frederik Harsdorff on the marble baths in Frederiksberg Palace (1770) and as executing architect on Frederick V's Chapel at Roskilde Cathedral.

In 1777, when Nicolai Abildgaard had returned to Denmark, Meyn finally went abroad to further his education, spending most of the time in Paris and Rome.

He served as acting master builder (konstitueret bygmester) for the Navy in 1785–88.