92-Year-Old Opposition Leader Wins Malaysia Presidential Election! See Photos

Malaysia's Mahathir Mohamad is now the world's oldest leader

Kuala Lumpur (CNN) — Veteran Malaysian politician Mahathir Mohamad has become the world's oldest leader after a shock victory in the country's election, upending six decades of control by the ruling coalition.

The 92-year-old was sworn in on Thursday night by Malaysia's constitutional ruler, King Muhammad V, following a momentous vote in which scandal-plagued incumbent Najib Razak was soundly beaten at the polls by his former mentor.

It's a triumphant return to front-line Malaysian politics for Prime Minister Mahathir, who also ruled the country from 1981 until 2003.