It debuted on Billboard's Digital Song Sales chart at number 36, and earned Anderson-Lopez and Lopez a Primetime Emmy Award for Outstanding Original Music and Lyrics, among other accolades.

In December 2020, songwriting couple Robert Lopez and Kristen Anderson-Lopez were announced to have written theme songs for some of the episodes of the Marvel Studios Disney+ miniseries WandaVision.

[1] The seventh episode of the series, "Breaking the Fourth Wall", which was released on Disney+ on February 19, 2021, ended by revealing that Kathryn Hahn's character Agnes was actually Agatha Harkness and the manipulator of Wanda Maximoff's idyllic suburban lifestyle inspired by American sitcoms in Westview, New Jersey.

[12] "Agatha All Along"'s chord progression begins in E minor before moving a tritone to B-flat in the bass, with a bridge centered in G major and a "Shave and a Haircut" ending.

[8][12] The song includes "a big-band horn riff",[14][15] "kitschy" electric harpsichord for the repeated chorus,[9][12] "cheery baritones",[9] a "'clap-clap, clap' snare",[13] and is sung in "kooky-spooky voices", with lyrics that reveal how Agatha had been behind all of the show's tragedies.

[23] Disney's president of marketing Asad Ayaz called the moment "a zeitgeisty thing" and his team quickly released the official clip after unofficial ones were going viral.

[16] The Los Angeles Times' August Brown agreed with Zalben that "Agatha All Along" was WandaVision's villain song, describing it as "a meme-able, deliciously vampy single that gleefully twisted the plot of the show" and one that would "likely live on outside it as entrance music for anyone looking to stir chaos".

[3] Writing for Polygon, Joshua Rivera felt "Agatha All Along" was Anderson-Lopez and Lopez's "finest moment" of WandaVision, calling the song the series' "first real earworm: short, sticky, and extremely meme-able".

[13] Lawrence's colleague Emma Fraser ranked "Agatha All Along" as the best of the WandaVision theme songs, believing it would lead to Anderson-Lopez and Lopez winning an Emmy.