Kathryn Hahn reprises her role as Agatha Harkness from WandaVision, with Joe Locke, Debra Jo Rupp, Aubrey Plaza, Sasheer Zamata, Ali Ahn, Okwui Okpokwasili, Patti LuPone, Evan Peters, Maria Dizzia, Paul Adelstein, and Miles Gutierrez-Riley also starring.

Schaeffer, Rachel Goldberg, and Gandja Monteiro were set as directors in early 2023 ahead of filming, which took place from January to May 2023 at Trilith Studios in Atlanta, Georgia, as well as in Los Angeles.

[2] Reprising their roles from WandaVision as Westview residents who play characters within Agatha's Agnes of Westview reality are Emma Caulfield as Sarah Proctor / "Dottie Jones", David Payton as John Collins / "Herb Feltman", David Lengel as Sarah's husband Harold Proctor / "Phil Jones", Asif Ali as Abilash Tandon / "Norm Gentilucci", and Amos Glick as a pizza delivery man / "Dennis Webber".

[27][28] The remaining six members of the Salem Seven are Marina Mazepa as "Snake", Bethany Curry as "Crow", Athena Perample as "Fox", Britta Grant as "Rat", Alicia Vela-Bailey as "Owl", and Chau Naumova as "Coyote".

[32] Hannah Lowther, Tetra Lloyd White, Henriette Zoutomou, Holly Bonney, and Kim Bass appear as witches trapped by Agatha and Nicholas during the 1750s.

[24] At Disney's biennial D23 Expo convention in August 2019, Kathryn Hahn was revealed to be cast in the role of Agnes, Wanda Maximoff and Vision's neighbor, in the Marvel Studios Disney+ television series WandaVision (2021).

[48] Actress Aubrey Plaza had previously posted a photo in May 2023 of a director's chair with that title, in a font based on the one used for the Disney film The Princess Diaries (2001).

[61] Squires, Cameron, Donney, and Monti all returned from WandaVision,[62][63] alongside Megan McDonnell, who was a consulting producer, serving as the on-set writer.

The series also draws from other well-known portrayals of witches, such as The Wizard of Oz (1939) and Maleficent (2014), incorporating visual cues and narrative elements inspired by these films.

[69] Early attempts at creating the trials were elemental based, which did not allow for the infusion of illusion or pop culture or the creativity from the costume and production design.

[71] Following the abundance of fan theories and speculation on WandaVision that ultimately were not intended for that series, Schaeffer was more careful with her language in Agatha All Along to still be able to protect some of the series' surprises while hoping it would not create expectations in the fandom that would not come to fruition,[72] dismissing such as Thanos appearing due to his backstory with Death in the source material, with Schaeffer intending to just leave some of Death's characterization for interpretation in the show.

[54] In January 2023, several cast members were revealed to be reprising their roles from WandaVision: Debra Jo Rupp as Sharon Davis / "Mrs. Hart";[15][27] David Payton as John Collins / "Herb Feltman"; David Lengel as Harold Proctor / "Phil Jones"; Asif Ali as Abilash Tandon / "Norm Gentilucci"; Amos Glick as a pizza delivery man / "Dennis Webber"; Brian Brightman as the Eastview, New Jersey, sheriff; and Kate Forbes as Agatha's mother Evanora Harkness.

[72] Principal photography began on January 17, 2023,[86][26] at Trilith Studios in Atlanta, Georgia,[87] with Schaeffer, Monteiro, and Goldberg directing episodes of the series.

[45] The start of the 2023 Writers Guild of America strike in May 2023 was not expected to impact production of Agatha All Along, with Marvel Studios reportedly planning to shoot what they could during principal photography and make any necessary writing adjustments during the series' already scheduled reshoots.

[5] Hahn, Locke, and LuPone promoted the series at Disney's May 2024 upfront presentation, where the release date and official title were announced and the first trailer was shown.

[2] Charles Pulliam-Moore at The Verge felt that the trailer was giving a "promising horror turn" and indicated that the series was darker and more "horror-oriented" than other Marvel projects.

[114] Jennifer Ouellette of Ars Technica wrote that the series looked like "a lot of dark, spooky fun" and was the perfect fit for releasing in the Halloween season.

[115] Two days after the teaser's release, Hahn, who had been guest hosting the late-night talk show Jimmy Kimmel Live!, ended her opening monologue with a song recapping the MCU.

[119][115][27] The series was previously expected to debut as early as late 2023,[47] but by February 2023 it was not included on a list of "sure bets" to be released that year amid Disney and Marvel Studios re-evaluating their content output.

[125] Streaming analytics firm FlixPatrol, which monitors daily updated VOD charts across the globe, reported that the series ranked in the top 10 across 56 countries and territories as of October 2.

[136] JustWatch, a guide to streaming content with access to data from more than 40 million users around the world, reported it among the top ten most-streamed series in the U.S. from September 16 to November 3.

[138] Whip Media, which tracks viewership data for the more than 25 million worldwide users of its TV Time app, revealed that it was the second most-streamed original series in the U.S. from September 22 to October 6.

[143] Luminate, which measures streaming performance in the U.S. by analyzing viewership data, audience engagement metrics, and content reach across various platforms, calculated that Agatha All Along was watched for 2,28 billion minutes in 2024.

The website's critics consensus reads, "The marvelous Kathryn Hahn is backed up by a coven of memorable performers in this MCU spinoff that refreshingly concocts its own distinct brew.

[147] Writing for the Rolling Stone, Alan Sepinwall noted that the series "works as a proper TV show rather than a chopped-up movie," while David Fear lauded the self-contained nature of the narrative, claiming it aligned with Disney+ output better than various other Marvel Studios properties.

"[150] Lucy Mangan of The Guardian gave the show a grade of 5 out of 5, and lauded its exploration of multiple genres, stating, "This royally entertaining Marvel series slips seamlessly from comedy to tragedy.

"[149] Paul Bradshaw of NME praised Hahn for grounding the show's shifting tone, calling her performance "never funnier, never better, in a role she plays like a shot in the arm for Disney".

[163] In addition to its queer themes, the series received praise from critics for its exploration of topics such as motherhood, community, and death, as well as its commitment to a villainous lead.

"[156] Writing for Vulture, Caroline Framke lauded the series' finale for depicting Agatha Harkness as a loving mother without negating her villainy or simplifying her motivations.

[166] The website went on to feature Hahn among their 20 finalists for Performer of the Year in December 2024, with R. I. praising her "delicate moments: her hints of genuine longing for Rio; the glimpses of grief over her son’s death; and her surprising — ill-advised, even!