A captured Ugandan rebel commander made his first public appearance Monday at a hearing before the International Criminal Court, where he stands accused of crimes including murder and enslavement.

Speaking calmly in his native Acholi dialect, Dominic Ongwen, a commander in the Lord’s Resistance Army, the rebel group that has terrorized parts of sub-Saharan Africa for decades, identified himself as a former child soldier born in northern Uganda in 1975. He also said “I’d like to thank God for creating Heaven and Earth, together with everyone that’s on Earth.”

Dressed in a dark suit, white shirt and blue and gray plaid tie, his hair closely cropped, Mr. Ongwen did not resemble his guerrilla photographs, which show a man with dreadlocks wearing a green military beret and camouflage fatigues.