Hilarious Hollywood legend and acting, writing, and directing genius Harold Ramis died early Monday morning in Chicago. Best known for his work on Animal House (1978), Caddyshack (1980), Ghostbusters (1984), and Groundhog Day (1993), Ramis was the man behind some of the funniest movies ever made. He was 69.

Ramis, a Chicago native, began his writing career in the mid-1960s, serving as a freelance writer with the Chicago Daily News and the joke editor of Playboy. During this time he was also heavily involved with Chicago's famed Second City.

In the 1970s, Ramis played a major role as a writer and performer, along with John Belushi and Bill Murray, on The National Lampoon Radio Hour, The National Lampoon Show, and SCTV (1976-1979). After leaving SCTV, Ramis co-wrote the script for National Lampoon's Animal House. He also wrote Stripes (1981), National Lampoon's Vacation (1983), Ghostbusters, Ghostbusters II (1989), and Groundhog Day.

But Ramis' skills weren't limited to writing. He also directed many of the films he co-wrote, including National Lampoon's Vacation, Groundhog Day, and Caddyshack, one of the one greatest sports movies of all time. And though he spent much of his time behind the camera, Ramis might be best remembered for starring as the beloved Dr. Egon Spengler in the Ghostbusters films as well as "Ben's Dad" in Knocked Up (2007).

Ramis' writing, acting, and directing have been credited with paving the way for many contemporary comedic filmmakers, such as Judd Apatow:

"When I was 15, I interviewed Harold for my high school radio station, and he was the person that I wanted to be when I was growing up," said Apatow, who later would cast Ramis as Seth Rogen's father in "Knocked Up" and would produce Ramis' final movie, "Year One" (1999). "His work is the reason why so many of us got into comedy. We grew up on 'Second City TV' and 'Ghostbusters,' 'Vacation,' 'Animal House,' 'Stripes,' 'Meatballs' (which Ramis co-wrote); he literally made every single one of our favorite movies."

According to his wife Erica Mann, Ramis died from complications of autoimmune inflammatory vasculitis, a rare disease that involves swelling of the blood vessels. He had been struggling with his health since 2010.

He is survived by his wife Erica, his daughter Violet Stiel, sons Julian and Daniel Ramis, and two grandchildren.