Holding the rank of four-star general,[10] he has served as the commander-in-chief of the Armed Forces of Ukraine since 8 February 2024.

[17] In 1980, when Syrskyi was 15, his father was transferred to serve in the Soviet Armed Forces in Kharkiv, Ukrainian SSR.

[14] In 2007 he was appointed as a Chief of Staff – first deputy of the United Operative Commander of the Ukrainian Armed Forces.

[24] Russian propaganda has spread fakes about Syrskyi, including that he has an adopted son in Australia.

In the winter of 2015, he went to the city with the Chief of the General Staff of the Armed Forces of Ukraine Viktor Muzhenko.

Oleksandr Syrskyi was awarded the Order of Bohdan Khmelnytsky III degree and later received the rank of lieutenant-general due to his achievement during the battle of Debaltseve.

During the Russian invasion of Ukraine, Syrskyi initially organised and led the defense of Kyiv.

On 28 April 2024, he announced that Ukrainian forces had retreated from the villages of Berdychi, Semenivka, and Novomykhailivka in Donetsk Oblast due to the positions becoming untenable.

He said "We will do everything we can to reach the internationally recognised borders of 1991," and talked about his planned use of the F-16 platform to intercept Russian cruise missiles.