Ukraine has made significant progress in the war in 2026, and a rift between the country's outgoing army chief and its defence minister threatened to derail its efforts.
Both men lost their jobs following Zelenskiy's major government reshuffle.
The top-level changes late on Tuesday were intended to draw a line under an unwelcome spasm of political turmoil that lasted almost a week and prompted rejoicing in Russia.
The new army chief, 43-year-old Major General Mykhailo Drapatyi, belongs to a new generation of Ukrainian generals who have come up through the ranks during the battle against Russian aggression.
He became known for his daring and courage in 2014, the year that Russia seized and illegally annexed Ukraine's Crimean Peninsula, and eight years before Moscow's all-out invasion.
Zelenskiy said Drapatyi and other commanders must present an updated defence strategy, including continued reform of the corps system, faster weapon and drone deliveries, stronger air defence against Russian strikes, and a clearer mobilisation plan.
Zelenskiy met separately Tuesday with outgoing defence minister Mykhailo Fedorov, a 35-year-old tech-savvy entrepreneur credited with swiftly developing Ukraine's drone technology that has given it a battlefield edge.
Fedorov locked horns with outgoing commander-in-chief General Oleksandr Syrskyi, a 60-year-old veteran trained in the Soviet Union before Ukraine's independence.
Street protests in Kyiv and other cities demanded Fedorov's return, viewing him as a key military moderniser, and urged Zelenskiy to fire Syrskyi, regarded as part of the old guard.
Zelenskiy offered Fedorov what he called a respected position in the government that would unify the country's technology sector.
It was not clear if Fedorov accepted the offer, or whether the latest moves would satisfy protesters and calm the streets.
Fedorov supported Drapatyi's appointment, calling it a "new hope in the fight of free people for freedom and justice" and "a voice for change that could not go unheard".
Fedorov had criticised Syrskyi publicly before his dismissal, saying the general was blocking his reform efforts and needed to be replaced for Ukraine not to fail in its resistance against Russia.
But Syrskyi defended his wartime record in a statement Wednesday.
Among other things, he claimed Ukrainian forces had clawed back more than 740 square kilometres of Russian-occupied Ukrainian territory in 2026 and said he was handing his successor an army that was not only defending but also conducting offensive operations.
It was not possible to independently verify his claim.
Fedorov called Syrskyi to thank him for his military triumphs, including defending the Kyiv region at the time of Russia's February 2022 full-scale invasion, the Kharkiv counteroffensive operation later that year and other battles, calling them "already an important part of Ukraine's history".
But he said the country must "move even faster and write new chapters, correcting all previous mistakes".
The political crisis began on Thursday, when Zelenskiy overhauled his wartime government, replacing his prime minister and firing Fedorov after just six months in the post.
The reshuffle immediately drew thousands of protesters into the streets of Kyiv and other cities, framing Fedorov's removal as Zelenskiy siding with an entrenched military old guard over a reformer.
Meanwhile, Ukrainian drones overnight struck two more sprawling warehouses of Russia's major online retailer, Wildberries, in Russia's southern regions of Krasnodar and Stavropol, Russian officials said on Wednesday.
The strikes came four days after Ukraine's long-range drones hit massive Wildberries warehouses in the Moscow region and in the Tambov region, killing eight people and wounding dozens, according to officials.
Zelenskiy said said the facilities were used by Russia to supply sanctioned components for the production of drones and navigation equipment.