pulled oneself up by one's bootstraps

To pull oneself up by one's bootstraps is to improve one's situation through hard work and self-reliance, without outside help: He pulled himself up by his bootstraps and built a successful business.

The phrase originally described something physically impossible—lifting yourself by tugging on your own boot straps.

That irony has largely faded; the expression now typically appears without skepticism in narratives of self-made success, though some use it critically to suggest that such advancement isn't as independent as claimed.