Born as a member of the House of Callimachi, he was the eldest son of Alexandru Callimachi and his wife, Ruxandra Ghica. He had one younger brother Ioann Callimachi (1775-1821) and two sisters, Eufrosina Sutzu (1776-1835) and Ralu Callimachi (b. 1771), first wife of Prince Constantine Ypsilantis. ^[1]

In 1810, during the Russo-Turkish War, he was imprisoned by the Russians, and taken to Kharkiv. He regained the Moldovan throne in 1812. Scarlat Callimachi adopted new laws and cut taxes for the Boyars. He took measures against the plague, maintained upkeep of wood paved streets, supported Gheorghe Asachi's Romanian-language movement, and introduced potatoes to Moldavia.

In 1819 Scarlat Callimachi was taken to Istanbul to be executed after being suspected of collaborating with the Russians. He managed to have the sentence cancelled and in 1821 was appointed by the Porte to be Hospodar of Wallachia. He was Prince de jure a few months in 1821 and was unable to claim the throne. The Greek War of Independence broke out in 1821, and Callimachi died poisoned later that year, under suspicion of being pro-Greek.

He was married to Smaragda Mavrogheni (1774-1837), daughter of Nicolae Mavrogheni (1735-1790) and his wife, Maria Scanavi (1755-1821). They had:

• Prince Alexandru Callimachi (1802-1879), married Princess Eufrosina Cantacuzino-Pascanu (1817-1875) and had issue
• Princess Ralu Callimachi (1803-1821), married Constantin Bogdan (adopted Palladi) (1792-1831) and had issue. Among their numerous descendants is Sophie, Princess of Albania
• Princess Eufrosina Callimachi (1810-1868), married Nikifor Papadopol (d. 1862). and had issue. Among them is Alexandru Papadopol-Calimah