President Volodymyr Zelenskyy has become the face of Ukraine’s resistance against Russian President Vladimir Putin’s invading forces, with impassioned speeches such as an address to the United Nations Security Council in which he accused Russian forces of committing war crimes.

Mr. Zelenskyy came into power with little traditional political experience. Since the Russian strikes began on Feb. 24, Mr. Zelenskyy has captured the world’s imagination, often dressing in military T-shirts or ballistic vests as he urges people to press the fight during videos he posts to Telegram, Facebook and Instagram from the center of Kyiv.

In Ukraine, his customary late-night addresses over social media have become a rally-point for ordinary Ukrainians. Seated at his desk, Mr. Zelenskyy provides updates on how the conflict is progressing, applauding the sacrifices of the Ukrainian armed forces and warning of the tests to come.

Mr. Zelenskyy has since been on a virtual tour of capitals to rally support for Ukraine. In addition to the U.N. and the U.S. Congress, he has addressed people in the U.K., Germany and Switzerland, among others, with plans for further outreach to seek assistance and keep international pressure on Russia.

Mr. Zelenskyy is married to Olena Zelenska. They have two children, a daughter, Oleksandra, and a son, Kyrylo.