When the question of overall commander arose Yudhishthira asked for the opinions of his brothers. Bhima suggested the name of Shikhandi, Arjuna proposed Dhrishtadyumna, Nakula and Sahadeva proposed the names of Drupad and Virat respectively. In the end Yudhishthira looked at Shrikrishna who agreed with Arjuna’s suggestion and that is how Dhrishtadyuma was chosen as the overall commander of the Pandava army throughout the entire 18 days of war.
Duryodhana picked up Bhishma to lead his army. He led the Kaurava army for the first ten days of the war. After the fall of Bhishma, Karna joined the battle and he proposed the name of Dronacharya as the next commander. Drona led the Kaurava army for the next five days. Drona’s role as a commander was the most action packed with Abhimanyu dying inside the Chakravyuha followed by Arjuna taking the vow of killing Jayadratha. The night battle after the fall of Jayadratha where Karna had to use the Vasavi dart on Ghatotkacha. All these events took place under the commandership of Drona.