His areas of research include war in antiquity, the Achaemenid Empire (First Persian Empire), the Hellenistic era after the conquests of Alexander the Great, the Hellenistic armies of the Greek successor states (diadochi), and the History of Crete.
He returned to academia in 1997 to work at the Institute of Archeology and Ethnology of the Polish Academy of Sciences in Warsaw.
His habilitation in 2002 was also with the Institute of Archeology; his resulting work was published in book form as Hellenistic Infantry Reforms of the 160's BC.
[4] Sekunda has participated in various archaeological excavations in England, Poland, Iran, Greece, Syria and Jordan.
He was a codirector of excavations, with Goran Sanev of the Archaeological Museum of Skopje, at Negotino Gradište [mk] in North Macedonia, a joint Polish-Macedonian project that began in 2009.