“I am honored and delighted to be joining English National Opera, a company whose consistently ambitious and thrilling work I have loved for all my opera-going life,” Ms. Miskimmon said in a statement. She was unavailable for interview, a spokeswoman for the London opera company said.

This will not be the first time Ms. Miskimmon has taken the reins of a troubled company.

She took over at the opera house in Oslo after its former director, Per Boye Hansen, was denied a contract extension. And before even taking up the post, she had a falling out with the company’s music director, Karl-Heinz Steffens. In April 2017, he announced that he would step down as soon as Ms. Miskimmon came in, writing in a resignation letter that “cooperation between us will not be possible.”

But Maren Orstavik, the opera critic for Aftenposten, a Norwegian newspaper, said in a telephone interview that the incident should not be taken as a sign of Ms. Miskimmon’s leadership style, and that Mr. Steffen had resigned out of loyalty to Mr. Hansen. “My impression is she’s been really well perceived,” Ms. Orstavik added, saying that Ms. Miskimmon had been a diplomatic leader in Oslo.

“She has a talent for seeing what audiences will like,” Ms. Orstavik said, as well as a sense of “what would be good artistically to try.”

Ms. Miskimmon comes from an opera-loving family in Northern Ireland, and watched her first production, Mozart’s “Magic Flute” when she was just 10. “From an early age, opera helped me escape the Troubles,” she told The Guardian in 2016, referring to the territory’s violent past. “Opera and theater were, and still are, a safe place for open-minded creative people from both communities, a defense against all the sectarian problems,” she added.