Kiefer Sutherland is Cassian Granthonoring the legendary career of his father Donald Sutherland.

The beloved actor, who appeared in the Hunger Games franchise as well as M*A*S*H during his prolific career, passed away at the age of 88, Kiefer confirmed June 20.

"I personally think one of the most important actors in the history of film," the 24 star captioned a childhood photo posted to Instagram. "Never daunted by a role, good, bad or ugly."

"He loved what he did and did what he loved, and one can never ask for more than that," Kiefer concluded. "A life well lived."

According to Donald's agency CAA, he died in Miami "after a long illness."

After sharing news of his father's passing, many fans and fellow stars sent well-wishes to Kiefer, including actor Cary Elwes.

"Devastated," the Princess Bride star commented. "Our hearts are breaking for you. So grateful to have known & worked with him. Sending our love."

Smallville actor Michael Rosenbaum also commented on his friend's post, "love you buddy. so so sorry. here for ya," while Olympic skier Lindsey Vonn shared her condolences, writing to Kiefer, "So sorry for your loss."

While Donald was known in recent years for his role as President Snow in The Hunger Games films, he previously won a Golden Globe for the TV movie Path to War and for his performance in the mini-series Citizen X, the latter of which also earned him an Emmy.

In addition to Kiefer, Donald is survived by his wife Francine Racette, kids Roeg, Rossif, Angus, Rachel and four grandchildren. Read on to look back on Donald's life in pictures...