Dmytro Kuleba -- who resigned as Ukraine's top diplomat Wednesday -- tirelessly toured the world pleading for more military support and for Kyiv to be given the green light to strike targets deep inside Russia.
The 43-year-old -- Ukraine's youngest ever foreign minister when President Volodymyr Zelensky appointed him in 2020 -- is the best-known figure to go in a major government reshuffle.
The son of an ambassador, the bespectacled career diplomat is one of the most talented public speakers in Ukrainian politics.
Kuleba became a familiar face in the West after the Russian invasion in 2022, championing Kyiv's position and appealing for weapons.
"We know how to win. And will win," he told "The Late Show" on US television in 2022, to thunderous applause from the studio audience.
But, like Zelensky, he also grew visibly frustrated by Western fatigue and slow weapon deliveries as the conflict dragged on.
"When Ukraine has everything it needs, we do not lack courage and military skill to advance and win," he told CNN this week, speaking about Kyiv's surprise incursion into Russia's Kursk region this summer.
Kuleba was also popular back home, and no reasons have been given for his departure.
But sources in Ukraine's presidential administration told AFP that he had been criticised for the functioning of his ministry and had been under pressure from Zelensky's chief of staff Andriy Yermak.
His deputy, Andriy Sybiga, a former ambassador to Turkey and ex-presidential office staffer, is rumoured to be replacing him.
Kuleba has spent recent months trying to persuade the West to allow Kyiv to use its weapons to strike military targets deep inside Russia, dismissing Western fears of escalation as an "excuse not to do anything".
But despite meeting some resistance from key allies, he earned admiration for his communication skills.
"Long conversations on night trains, at the G7, on the frontlines, in Brussels, in front of a bombed-out power plant," said German Foreign Minister Annalena Baerbock on X, reminiscing about their relationship.
"There are few people I've worked as closely with as you," she added.
Ukrainian political scientist Mykola Davydiuk told AFP that Kuleba was "one of the best Ukrainian foreign ministers," adding: "He was not corrupted and acted like a pure western diplomat, speaking several languages and communicating with everybody" without stealing the limelight from Zelensky.
Born in Sumy -- a city in northeastern Ukraine now regularly shelled by Russia -- Kuleba studied international relations in Kyiv.
He built a diplomatic career in the early 2000s, but quit in 2013, denouncing former pro-Russian president Viktor Yanukovych and joining the Maidan protest movement that overthrew him.
He rejoined Ukraine's foreign ministry in 2014, the tumultuous year when Russia annexed Crimea with war breaking out in the east.
Sybiga's appointment as Kuleba's second in command in April was seen as a bid by the presidential office to better control the foreign ministry.
