Following Witness, Mortensen portrayed several bad boys and finally attained greater recognition in Portrait of a Lady (1996), G.I. Jane (1997) and A Perfect Murder (1998), where he played opposite Michael Douglas and Gwyneth Paltrow.
Mortensen's luckiest break came when director Peter Jackson began shooting the Lord of the Rings trilogy and decided, a few days into it, to recast the role of Aragorn with Mortensen. Much criticized during its 18-month production in New Zealand, the trilogy went on to be a huge success, sweeping the 2004 Oscars by winning all 11 categories for which it was nominated. Four years later, Mortensen's leading role in Eastern Promises brought him an Oscar nod.