But Karolyn Grimes, now 74, looks back and sees meaning in her journey, which in many ways started on the set of Frank Capra's beloved 1946 holiday movie (which NBC is airing again Christmas Eve).
"It's all in how you look at your life, because no one has a wonderful life. But you can make it what you want it to be," Grimes tells Seattle's KOMO-TV.
Grimes endured pain beginning as a child. Both of her parents died by the time she was 15. Married young, she soon divorced, and her ex-husband died in a hunting accident. Her second husband died of cancer. And most difficult of all, her son committed suicide at 18.
"He was a good kid," Grimes says today, admitting the guilt never really went away. "I chose to face it. Feel it. And release it," she says. "I did the best I could."
Grimes says the optimistic message of It's a Wonderful Life, which she helps to spread through personal appearances, resonates because it acknowledges life's hardships. And in a way, the role she played as a child turned out to be the most meaningful of her life.
"It has put me on a path," she says. "I am not longer Karolyn, so much as I really am Zuzu."
The best part for Karolyn, is the mail she gets from fans. "The letters I get are just incredible," she says. "They love the movie, they thank me for being in the movie. What a great gift I've been given. And I don't take it for granted, I really don't."