He succeeded at the expense of his friends.
at the expense of sb/sth
idiomwhen you do something that causes harm or loss to someone or something else in order to succeed.
The company increased its profits at the expense of the environment by ignoring safety regulations.
The politician sought to advance his own career at the expense of the public trust, eventually alienating the very voters who had once supported his platform.
Last updated April 22, 2026