on the coattails of (someone)
Benefiting from someone else's success; using someone else's success as a means to achieve one's own. Everyone knows you've been on the coattails of the governor these last two years, but once her term ends, you'll be on your own. A: "I can't believe Jonathan got his paper published in that prestigious journal." B: "Oh, it's only because he's riding on the coattails of his professor."
on the coattails of
1. As a result of the success of another: elected to office on the coattails of a popular governor.
2. Immediately following or as a direct result of: resigned on the coattails of the scandal.