The producer who brought A Charlie Brown Christmas to life passed away on December 25.

Lee Mendelson also wrote the lyrics to "Christmas Time Is Here," the song known to characterize A Charlie Brown Christmas.

Mendelson's son, Jason, says he passed away Christmas Day at the age of 86 of congestive heart failure after fighting lung cancer. He passed away at his Hillsborough home in California, NBC News reports.

Mendelson is survived by his wife, five children, and eight grandchildren.

The producer won a dozen Emmy Awards in the course of his career. His work alongside Bill Melendez and Vince Guaraldi, as well as Peanuts author Charles Schultz, introduced the Christmas tradition of Charlie Brown to the world.

In 2000, Mendelson shared in an interview how "Christmas Time Is Here" came to be. With a tight deadline to find someone to write the words to the song, he decided to come up with them himself and penned the six verses in "about 15 minutes on the backside of an envelope."

The song's known choral sound came from a church choir in California, where Mendelson was from.

Every year, A Charlie Brown Christmas continues to air on television and delight audiences of all ages. The show won an Emmy Award and a Peabody Award.

Mendelson's team stayed together after the success of the show, creating four feature films, more than 50 network specials, and continuing the world of Peanuts.

The producer was born in San Francisco in 1933 before his family moved to San Mateo and eventually Hillsborough. In 1954, Mendelson graduated from Stanford and served in the Air Force. He was working for a fruit and vegetable company owned by his father when he eventually decided to enter the world of television.

His first documentary after opening his own production company in 1963 was a home run. It focused on the life of Willie Mays, a center fielder for the San Francisco Giants.

After A Man Named Mays, Mendelson joked that he moved from the world's greatest baseball player to the worst. He took on a "Peanuts" documentary alongside Schultz that saw little success in television until halfway through 1965 when they were asked to take turn the comic strip into an animated Christmas special. 

The producer didn't limit himself to the world of Charlie Brown. Mendelson was responsible for several comic strips coming to life on television, including Garfield.

Schultz wrote the now-classic A Charlie Brown Christmas focused on a sad Charlie Brown looking for the meaning of Christmas. Guaraldi, a pianist and composer, was hired to provide the music.

The reaction to the show was not what the team hoped for when they first showed the special to CBS executives. A week before it was to go to air, the team was told by executives that they hated it.

But the simple story with biblical themes became a hit that holiday season. In 2015, Mendelson spoke about the legacy of the television special.

"It was just passed on from generation to generation," Mendelson says.

"It became part of everybody's Christmas holidays."