Christine M. McCarthy, who in her eight years as Disney’s chief financial officer helped stabilize the company during the pandemic, when most of Disney was shut down, and played a key role in the ouster of Bob Chapek as chief executive last year, will step down on July 1, she said on Thursday.

Ms. McCarthy, 67, said she would take a “family medical leave of absence.” Disney provided no further details, although it is well known within the company’s senior ranks that her husband has a serious illness. Ms. McCarthy, who has twice battled cancer during her Disney career, has a contract that runs until next June.

She will serve as a strategic adviser until then and help “identify and onboard a long-term successor,” Disney said. Kevin Lansberry, 59, will be the company’s interim finance chief. He has served as chief financial officer for Walt Disney Parks, Experiences and Products since 2017. “He has my complete confidence,” Robert A. Iger, Disney’s chief executive, said in a statement.

Mr. Iger called Ms. McCarthy “one of the most admired financial executives in America” and said her impact on Disney could “not be overstated.”

In February 2020, just as the pandemic was starting to shut down much of the world economy, Mr. Iger stepped down as Disney’s chief executive and turned the job over to Mr. Chapek, the company’s former theme park chairman. Together, Mr. Chapek and Ms. McCarthy raced to put Disney on the most first firm financial footing possible, including by securing $20 billion in the bond markets.

“Christine was able to raise the right kind of debt instruments to keep us afloat,” Kevin Mayer, Disney’s former streaming chief, told a reporter for Smith College’s alumnae magazine last year.

By last fall, however, the relationship between Ms. McCarthy and Mr. Chapek had curdled. She had become increasingly alarmed about losses at the company’s streaming division and privately questioned whether Disney+ could meet the aggressive subscriber targets that Mr. Chapek was publicly touting.

The friction broke into view at a Disney board meeting — Ms. McCarthy bluntly told the board what she thought, enraging a surprised Mr. Chapek — and he never recovered; the board fired him in late November. (In May, Mr. Chapek and Ms. McCarthy were both named in a shareholder lawsuit accusing the company of misleading investors about Disney+ growth. Disney said at the time that it would defend itself in court.)

Mr. Iger agreed to come out of retirement to retake Disney’s reins. Ms. McCarthy, who had remained close to him, was the one who made the first call to him to see if he was interested.

Ms. McCarthy joined Disney in 2000 as treasurer. She previously spent two decades in the banking industry.