“充当配角”常见的英文表达有：play a supporting role 、serve as a supporting character 。
play a supporting role：这是较为常用和简洁的表达，强调在某个情境、活动或项目中起到辅助、次要的作用。
例句：In this movie, he plays a supporting role but still leaves a deep impression on the audience.（在这部电影里，他虽然充当配角，但依然给观众留下了深刻的印象。）
serve as a supporting character：更侧重于在戏剧、影视等文艺作品中担任次要角色，突出角色的性质。
例句：She often serves as a supporting character in TV dramas, but her performance is always outstanding.（她经常在电视剧中充当配角，但她的表演总是很出色。 ）