Market Basket has named Don Mulligan as the Massachusetts-based supermarket chain's interim Chief Executive Officer. He replaces fired CEO Arthur T. Demoulas.

The board of directors made the announcement Tuesday. Mulligan joined the company 42 years ago and has been Market Basket's chief financial officer for the last 26 years.

Board chair Jay Hachigian called Mulligan "the voice of consistency at Market Basket."

"The Board has worked closely with Mr. Mulligan and has come to appreciate his exceptional business acumen, the respect and admiration our associates have for him, and his deep understanding of the history and culture that make Market Basket so special," Hachigian said in a statement.

"We are thrilled to have a homegrown leader of Mr. Mulligan's caliber step into the role of Interim CEO to guide Market Basket and ensure seamless leadership for our associates, customers, and communities."

Mulligan graduated from Lowell High School and UMass Lowell, the company said. 

Demoulas, 70, was fired on September 9, after a long struggle with the board and his three sisters for control of the company, which is based in Tewksbury. Demoulas, two of his children and two executives who supported him were all suspended and put on paid leave on May 28. The board accused Demoulas of planning a work stoppage, similar to a boycott in 2014 that ended with Demoulas taking over the company. He called the new investigation a "farcical cover for a hostile takeover."

Demoulas and the board met with a mediator in Delaware earlier this month, but failed to reach an agreement on how the company should move forward. Demoulas is contesting his termination, the board said in a court filing last week.

According to the board, Arthur T. Demoulas currently owns 28.4 percent of Market Basket. His three sisters collectively own 61.3 percent. The other 10.3 percent is in a trust for the 14 children of Demoulas and his sisters.