look after number one

look after number one

To put one's own needs, concerns, or responsibilities before those of anyone else. The only way you're going to get ahead in this business is if you look after number one. It doesn't make you a selfish person if you look after number one from time to time. Just don't do it exclusively.
See also: after, look, number, one
Farlex Dictionary of Idioms.

look after number one

 and look out for number one
to take care of oneself first. You gotta look after number one, right? It's a good idea to look out for number one. Who else will?
See also: after, look, number, one
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

look after number one

or

look out for number one

If someone looks after number one or looks out for number one, they selfishly consider their own needs and interests and no one else's. This sums up the attitude of many greedy big earners — look after number one and to hell with everyone else. My priority is to look after number one — to create a lifestyle I am happy with.
See also: after, look, number, one
Collins COBUILD Idioms Dictionary, 3rd ed.

look after number one

in. to take care of oneself first. (see also number one.) It’s a good idea to look after number one. Who else will?
See also: after, look, number, one
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • at will
  • be on (one's) pat
  • be hoist by (one's) own petard
  • be hoist with (one's) own petard
  • be hoist with one's own petard
  • be hoist/hoisted by/with your own petard
  • be on (one's) tod
  • about (one's) business
  • about business
  • a/(one's) 20