After listening to an upbeat song, he suddenly felt energized and full of life.

energized 是动词 energize 的过去分词形式。energize 由名词 energy（能量）加上动词后缀 -ize 构成，意思是"给予能量、使充满活力"。energized 在这里表示"被注入能量、变得精力充沛"的状态。