Mr. Mitsotakis earned a bachelor’s degree at Harvard and a master’s at Stanford before returning to Harvard for a master’s in business administration. He worked at Chase Investment Bank and McKinsey and Company, a consulting firm, in London, before deciding to try his hand at politics.

He says that his last name helped him with his first election as a member of Greece’s Parliament, but that, if anything, it has increasingly been a burden. “I don’t see people voting for me for coming from a political family,” he said in a recent interview. “I see people voting for me despite me coming from a political family.”

Yet it may be fair to say that he might never have become prime minister had he not been his father’s son. Liberals in Greece are considered something of an oddity, and hardly ever make it into Parliament.