Robert Morse, an American actor best known for his role as Bertram Cooper in “Mad Men,” died on Wednesday at age 90.

He passed away peacefully at his home in Los Angeles after battling a short illness.

The news of Morse’s death was confirmed to CNN affiliate KABC by his son, Charlie.

Born on May 18, 1931 in Newton, Massachusetts, Morse was an acclaimed stage and screen actor with an impressive career that spanned over 60 years.

In addition to his “Mad Men” role, Morse was also known for his starring role as J. Pierrepont Finch in the 1961 Broadway production and 1967 film adaptation of “How to Succeed in Business Without Really Trying.”

In this role, Morse transformed himself into an ambitious window washer who quickly became board chairman of a large company. The stage version of the show, which ran more than 1,400 performances over three-and-a-half years in the early 1960s, earned seven Tony Awards, one of which went to Morse for Best Actor in a Musical.

This win was only the beginning of a steady flow of prestigious awards for Morse. He won another Tony Award in 1990, this time for Best Actor in a Musical in recognition of his role as Truman Capote in the one-man play “Tru.” This same role also earned him an Emmy Award for Outstanding Lead Actor in a Limited Series or Movie thanks to a live performance of the show that was taped for PBS’ American Playhouse.

Younger audiences are more likely to recognize Morse for his role in “Mad Men.” This role resulted in Morse receiving five Emmy Award nominations for Outstanding Guest Actor in a Drama Series. Morse also received four Screen Actors Guild Award nominations for Outstanding Ensemble in a Drama Series, one of which resulted in a win.

Since Morse’s passing, colleagues like writer-producer Larry Karaszewski have voiced their grief in conjunction with their appreciation for the award-winning actor. Karaszewski took to Twitter to share memories of Morse, such as those gathered on the set of “People v OJ” and the many screenings the pair of friends hosted together.