work way up
work (one's) way up
To start at humble or modest beginnings, but rising in position, importance, or influence through hard work and determination. Just look at Johnson if you need proof: He started in the mail room, but worked his way up to one of the top lawyers at the firm. She worked her way up from a small one-woman online business to a media empire that employs thousands around the globe.
work one's way up
(to something) Go to work oneself up (to something).