Zai was born in Cannstatt, studied at the Karlsschule Stuttgart, and was taught by Karl August Friedrich von Duttenhofer and Johann Jakob Atzel.

Zais designed a number of important buildings in the spa town, including the construction (1808-1811) of the Old Kurhaus Wiesbaden, the Erbprinzenpalais at Wilhelmstrasse (used today as the Chamber of Commerce) in 1813, and the Four Seasons hotel which was destroyed during Allied bombings in 1945.

[1][2] He promoted the use of cheaper materials at the time, including extensive use of rammed earth; some of these constructions remain to this day.

Zais faced strong opposition from the city's inhabitants while implementing his ideas, which were backed by William, Duke of Nassau, operating from his Biebrich Palace residence.

Facing brisk opposition again from the local community, which sabotaged the spa's water sources, Zais died in Wiesbaden before the project's completion.