The Critic's feud with The Angry Video Game Nerd (2004) started as a joke when the Critic complained about the Nerd's fans comparing them. Doug Walker didn't expect James Rolfe to acknowledge him, but when he stated on his site that he was a fan, Walker contacted him about keeping a feud going. This became one of the show's best-loved running gags, culminating in no fewer than three in-person confrontations between the Critic and the Nerd, and leading to a real-life friendship between Walker and Rolfe.

Doug Walker's favorite critics of all time are Gene Siskel and Roger Ebert. To show his appreciation of them, he made Nostalgia Critic: A Tribute to Siskel and Ebert (2009). Also, when Ebert died, he made Nostalgia Critic: Farewell to Roger Ebert (2013).

Throughout the course of one year, Doug Walker has developed laryngitis a total of 3 times, mainly because playing the Nostalgia Critic requires him to scream repeatedly. Also, the voice of Chester A. Bum puts a strain on his vocal chords.

The first 14 episodes were recorded and produced in 2007 and posted on Doug Walker's YouTube page. When the videos were removed for legal reasons in 2008, Walker brought them to his own channel on, where he continued producing new Nostalgia Critic reviews on a weekly basis, and the rest is history.

Although the Critic frequently mocks Michael Bay and his movies, the very first review that he ever released was of Bay's first Transformers (2007) film in July 2007, a movie that he ironically seemed to enjoy.

The Critic often uses the term "Big-Lipped Alligator Moment" to describe moments in movies that come right out of nowhere, have little to no bearing whatsoever on the plot, are way over-the-top in terms of ridiculousness even in the context of the movie, and after they happen, no one ever speaks of them again. This is named after a scene in the film All Dogs Go to Heaven (1989), where a big-lipped alligator appears, has a random musical number, then is never mentioned again. Ironically, the term was originally coined by the Nostalgia Chick, not the Critic.

Many of the Nostalgia Critic's jokes were written by Doug Walker's brother, co-writer, and camera man, Rob Walker.

Doug Walker has stated that he draws a lot of inspiration for the Nostalgia Critic character from Jack Lemmon's performance in the film The Great Race (1965), as well as Daffy Duck cartoons.

For the first few years of the series, Doug Walker had established a cut-off date for the movies and shows he reviewed to be no later than 2001, owing to his character's title of NOSTALGIA Critic, with remakes and adaptations being the exception to the rule. However, when the series was revived in 2013 after a brief cancellation, Walker did away with the cut-off date to review more recent movies and shows, in addition to older ones. In 'The Review Must Go On', the character says he won't review anything "still in theaters." But in 2015, he relaxed that rule by introducing videos that reviewed films still playing at the box office by way of reenactments.

Nostalgia Critic was at one point going to review Matilda, but decided not to after fans of the movie told him not to.