SEOUL, South Korea — When President Trump wanted to highlight the brutality of North Korea’s government during his State of the Union address on Tuesday, he pointed to a man in the audience who had traveled thousands of miles on crutches to find freedom.

The story that man, Ji Seong-ho, tells of his escape is remarkable even by the standards of North Korean defectors. When Mr. Trump pointed him out, Mr. Ji jubilantly raised his crutches as television cameras captured the moment.

In 1996, Mr. Ji was 13, his parents’ eldest son, living in a mining village near the city of Hoeryong in northern North Korea. The country was in the midst of a famine that would kill more than two million, by some estimates. Surviving on roots and corn stalks, Mr. Ji’s family became so weak that they spent most of the day lying on the floor, sometimes hallucinating, he said in a 2014 interview.

His grandmother had died of hunger the previous year. In school, teachers were too weak to teach. Few students showed up to class.