Kaitlin Olson's Tribute to Her Late Father Describes How He "Fought So Hard" in the End

High Potential and It's Always Sunny in Philadelphia star Kaitlin Olson paid tribute to her late father, Don Olson, in an Instagram post following his death. She wrote about her dad's impact on her life and how she didn't want to share the post at first, but later thought it felt "wrong" to just move forward with her life without mentioning him.

Kaitlin's husband and It's Always Sunny co-star, Rob McElhenney, commented on the post to share his own thoughts about his late father-in-law. Other celebrity pals shared condolences of their own, and fans began to wonder what happened to Kaitlin's dad. Up until that post, she had not shared details about his health and had, it seemed, preferred to keep that part of her private life to herself.

On May 18, 2026, Kaitlin posted a handful of photos of her father and herself with her dad from over the years. In the caption, she shared the news of his death and added that she felt "lucky" to not only have had him as a father, but to have been there with him during his final moments before he died.

"Honestly it feels a little gross to bring this to social media," she wrote. "It's too fragile and too private. But nothing feels more wrong than to just move on with life as if the worst thing in the world didn't happen. As if everything that matters didn't just suddenly end. My dad died. My first love, my first protector and my forever favorite person. He fought so hard and so long to stay with us. I hate words right now. None are good enough to describe who he was."

Although Kaitlin wrote in her tribute to her dad about him fighting hard and about being there by his side in his final moments, she didn't disclose his exact cause of death. It's possible that he quietly battled an illness or diagnosis that Kaitlin didn't feel the need to share before or after his death. Since she noted in her tribute that it felt "gross" to post about her dad's death even now, it makes sense that other details have been kept private.

After Kaitlin posted her tribute to her dad on Instagram, Rob commented to share his own thoughts on losing his father-in-law. He wrote that he is "grateful" to have been Don's son for 17 years as Kaitlin's husband.

"Words are impossible," Rob wrote in the comments. "There is no one like him. My whole goal in life is to be half the man he was. I've never seen a person love someone the way he loved you."

According to The Portland Tribune, Kaitlin's dad Don was a publisher for the newspaper from 2000 until 2001. Unlike Kaitlin and Rob, he led a more private life out of the public eye.