In 1723 he travelled to Stockholm in order to hire the most highly skilled masons for the tsar.
During the early part of his career, Zemtsov participated in designing the Summer Garden in St Petersburg and the park in Peterhof Palace.
The other project in which he was involved was the design of Catherinethal palace and park in Reval (1718–25).
Zemtsov was appointed one of the principal architects of the Russian capital in 1737, working on the Transfiguration Cathedral in St. Petersburg along with Pietro Antonio Trezzini.
He completed his work on the Russian Building Code two years before his death.