Tsakaloff was born in Giannina, Epirus about 1790 into the wealthy Tekelis clan which prospered mostly outside the Ottoman Empire. His father was Nikiforos Tekelis, a furrier, originally from Tyrnavos, Thessaly.
The Tekelis-Tsakaloff family migrated to Moscow, Russia. Later, Athanasios left for Paris for studies. He returned to Moscow in 1813. Later that year he met Nikolaos Skoufas and Emmanouil Xanthos in Odessa. In 1814, the three men founded the Friendly Society.
Over the next three years Tsakaloff travelled to Constantinople, Smyrna and various parts of Greece recruiting members for his Friendly Society. The death of Skoufas in 1817 forced him to return to Constantinople where he shouldered the responsibility of running the Society with Xanthos.
In 1818, Tsakaloff took part in the execution of a Friendly Society member named Nikolaos Galatis who had been suspected of planning to betray his comrades. Following the killing, Tsakaloff fled first to Mani then to Pisa, Italy.
Early in 1821, Alexandros Ypsilantis crossed the Prut river and started the revolt against the Ottoman Empire in Moldavia. Tsakaloff joined him and fought in the Battle of Dragasani. Afterwards, as the revolt died down in Moldavia, he left for Peloponnesus where the uprising had taken root and placed himself under the command of Dimitrios Ypsilantis.
After Greece became independent in 1830, Tsakaloff served in several minor posts until the assassination of Ioannis Kapodistrias. Afterwards, disillusioned, he returned to Moscow where he married and stayed until his death in 1851.