President Donald Trump on Saturday welcomed former missionary Joshua Holt home to the U.S., telling the Utah native that securing his freedom from a Venezuelan prison was “a tough one.”

Mr. Holt, 26 years old, had been held for two years on espionage charges without facing trial. He was released Saturday by President Nicolás Maduro’s authoritarian government as an olive branch as it faces intensifying U.S. sanctions.

Mr....