at one's heels meaning

• [American slang]
  adv. phr. Close behind; as a constant follower or companion. The boy got tired of having his little brother at his heels all day. John ran by the finish line with Ned at his heels. Bad luck followed at his heels all his life.
  

• back on one's heels:    1. Driven back by ...
• cool one's heels:    Verb: cool one's h ...
• dig in one's heels:    To behave stubborn ...