Also,
be in with;
get on someone's good side. Be in someone's favor, be well liked by someone. For example,
He's in good with the higher-ups so we can expect approval of our application, or
I'd love to be in with that popular crowd, but I don't quite know how, or
I don't know how he got on her good side after that fight they had. The first two terms date from the 1900s, the third from the late 1600s. Also see
in bad with;
in favor with;
in someone's good graces.