Gary Sinise Son Cause of Death: How Did Mac Sinise Die?

Heavy/Getty Gary Sinise's son Mac Sinise died of cancer.

Fan-favorite entertainer Gary Sinise and his family are grieving after the death of a family member. Sinise’s son, McCanna Anthony “Mac” Sinise died at the age of 33 after a lengthy battle against a rare form of cancer.

Here’s what you need to know:

McCanna Anthony Sinise Died of Cancer

On February 27, Gary’s Foundation created a page honoring Mac. The page paid tribute to the life Mac led and revealed his death after a heartbreaking battle with cancer. The “CSI: New York” star signed the tribute, “Gary Sinise, Proud father of Mac Sinise.”

Mac received a diagnosis in August 2018 of a very rare type of cancer, Chordoma. His diagnosis came just weeks after his mother, and Gary’s wife, Moira received a stage 3 breast cancer diagnosis.

According to the Mayo Clinic, Chordoma is “a rare type of bone cancer that happens most often in the bones of the spine or the skull.”

That type of cancer “Can be difficult to treat because it’s often located very close [to] the spinal cord and other important structures, such as the arteries, nerves or the brain,” the clinic continued.

Gary shared that Moira went into remission after treatment and has remained healthy. Mac’s journey was far more difficult.

Mac had surgery in September 2018 to remove the tumor that was discovered. In May 2019, testing and imaging revealed Mac’s cancer had returned. The cancer was found to be spreading, too.

Mac “Died on January 5, 2024 at 3:25pm, and was laid to rest on January 23rd,” Gary shared.

Mac Sinise Died After a Brief Hospitalization

On December 30, 2023, Gary wrote, “We had to take Mac to the emergency room for what would be his final trip to the hospital.” The “CSI: NY” star explained, “He was having trouble getting his breath and after stabilizing him, he was admitted.”

In the initial days of that hospitalization, Gary noted that Mac seemed to be making a recovery. Unfortunately, “The days got tougher, and on January 5th, with the family all around him, he let go.”

“His battle with Chordoma was over and he was at peace,” Gary shared.

“In sharing our story, we hope to shine a little bit of light on what has been a difficult time for us as Mac was truly a light for all of us,” Gary’s tribute wrote.

He also wrote, “Even with one setback after another, he never stopped living and learning, creating, and giving, and loving.”

The actor’s colleagues and fans flooded the comments section of his Instagram post with love and support.

Gary’s “CSI: NY” co-star Melina Kanakaredes wrote, “Gary, our deepest sympathies. Sending you, Moira and the girls so much love and light! May Mac’s memory be eternal.”

Angie Harmon commented, “We are so sorry Gary. You & your family are deeply loved by so many. We are praying for all of you. Love you so very much.”

“Oh Gary. I’m so sorry,” wrote Katharine Foster.

A supporter shared that her veteran father died of cancer just before Christmas. “Your foundations and the work that Mac did is so very appreciated by us military families,” she wrote. That commenter added, “His legacy and music will live on. I pray he is at peace in the arms of our Lord.”