Founded in 1669 by Louis XIV, and with a modern-day budget of over 200 million euros, the Paris Opera is one of the oldest and most powerful music-theater companies in the world. But it has struggled to find a successor to Stéphane Lissner, its director since 2014.

An extended search ended on Wednesday, when the company announced that Alexander Neef, the general director of the Canadian Opera Company in Toronto, would take on the position, starting in 2021.

“It’s a pretty emotional day, obviously,” Mr. Neef, who was born in Germany, said in a telephone interview from Santa Fe, N.M., where he is also the artistic director of Santa Fe Opera. “It’s a big honor and a big responsibility.”

Widely admired for his work in Toronto, Mr. Neef, 45, is no stranger to the Paris Opera, where he was casting director from 2004 to 2008, working under his mentor, Gerard Mortier. He also held positions alongside Mortier at the Salzburg Festival and the Ruhrtriennale, and during Mortier’s brief time leading New York City Opera.