His father was Kallikratous and he was a nephew by marriage of the Athenian demagogue Agyrrhios, though whose sister married whose brother is unknown.
The earliest mention of Kallistratos was in 379 when the Theban Pelopidas used his name to gain entry to the home of his rival Leontidas in order to assassinate him.
This was the opening gambit in the anti-Spartan party's campaign to retake control of the Theban government and expel the Spartan garrison occupying the Kadmeia.
He was already a force in Athenian politics, though, and the next year, after the aborted invasion of Attica by the Spartan Sphodrias, he was elected strategos along with Timotheos and Chabrias.
[4] In 375, during the negotiations that led to the peace treaty ending the war, he is recorded as trying to convince the Theban delegation to give up their dream of uniting the cities of Boeotia in a federation.
Demosthenes reports that two heads of state, Alketas of Makedon and Jason of Pherai (Thessaly) came to Athens to support him at the trial and this helped secure his acquittal.
His treasurer and confidential agent Antimachos, however, was found guilty, condemned to death, and had his property confiscated by the state.
At this event, three Athenians spoke in an effort to convince the Spartans to accept the peace: Kallias tried to paper over the differences between the two cities; Autokles berated the Spartans for past sins; and Kallistratos, striking a more conciliatory tone, admitted that both sides had made mistakes and they had different interests, but these were no reason to destroy each other in constant war.
The eloquence of Kallistratos at the trial convinced the jury to acquit them, and in the process inspired a young Demosthenes to embark on a career in oratory.
[14] Kallistratos eventually did make it to Thasos and from there, in c. 360, was instrumental in helping the Thasians found a colony at Datos, across the strait in Thrace in the territory of Edonia.
The Social War, where Athens was fighting several of its allies, concluded that year and it is possible that Kallistratos saw an opportunity to repatriate at this time of renewed peace.