In 1574 he moved to Heidelberg and became court physician to the Elector Palatine, Frederick III.

When Frederick died in 1576, he was succeeded by his Lutheran son Elector Louis VI who removed the Reformed faculty from the University of Heidelberg, Smet briefly practiced medicine in Frankenthal.

After 1579 he entered the service of Count Palatine Johann Casimir and began to give medical lectures in the Casimirianum in Neustadt.

He returned to the University of Heidelberg with the rest of the medical faculty in 1585 after Johann Casimir became the regent of the Palatinate.

He compiled a dictionary of Latin words, which was so successful that it was frequently reprinted throughout the seventeenth century.