The song also reached number one in Australia, Canada, and Singapore, and the top 10 in Belgium, Croatia, Hungary, Ireland, Malaysia, New Zealand, and the United Kingdom.

After its release, the album's co-producer Aaron Dessner composed an instrumental track "Westerly", named after the location of Swift's Rhode Island home.

Greg Calbi and Steve Fallone mastered the track at Sterling Sound, Edgewater, New Jersey, while Jonathan Low mixed it at Long Pond Studios in Hudson Valley, New York.

[4] On December 13, 2020, Swift's 31st birthday, an electronic "Dancing Witch" version of "Willow" was released, remixed by Swedish producer Elvira Anderfjärd.

[18] It is built around a glockenspiel, drum machines, cello, French horn, electric guitars, violin, flute, and orchestrations, and is characterized by its "breathless" chorus.

[24] In his album review for The New York Times, Jon Pareles complimented the song's "restlessly intertwined guitar picking" as one of Evermore's numerous musical flourishes.

[25] Paste critic Ellen Johnson commended the song as a "graceful opener" to Evermore,[26] while Bobby Olivier of Spin called it an earworm suited for beach bonfires.

[27] Writing for The Guardian, Alexis Petridis opined that "Willow" could easily function as a "pop banger" if synthesizers, auto-tune and programmed beats replaced its "tasteful" acoustic arrangement.

[28] Variety's Chris Willman wrote that the song represents Swift's state of mind, and deemed it a cousin to "Invisible String" and "Peace", the eleventh and fifteenth tracks on Folklore (2020), respectively.

[note 2] It made her the first artist in history to debut an album and a single at number one simultaneously on two occasions, previously achieving it with Folklore and "Cardigan" (2020).

The song became Swift's 29th top-10 hit on the Hot 100, surpassing Mariah Carey and Stevie Wonder as the artist with the sixth most top-10 entries in the chart's history, and extended her female record for the most debuts in the top-10, with 19.

[31] On the chart dated January 2, 2021, it descended to number 38 on the Hot 100, breaking the record for the biggest fall from the number-one spot at that time.

On the Billboard Hot Alternative Songs chart, Swift claimed 16 spots led by "Willow", besting Machine Gun Kelly's 12 simultaneous entries.

[36] On the UK Singles Chart, "Willow" arrived at number three, shifting 35,183 units in its opening week;[37] it was blocked from the top spot by two Christmas songs.

"Willow" opened atop the ARIA Singles Chart, garnering the singer her seventh Australian number-one hit, and the second in 2020 following "Cardigan".

She then realizes that the only way out is to follow the magical thread through the rabbit hole under floor of the glass box, a scene that may represent Swift reaching her lowest moments before finding a golden path once more.

[45] She is joined by other hooded dancers who gather in a circle to perform a ceremony around a bonfire that oozes lots of golden mist and magical orbs.

Swift exits the piano wearing a new gown, representing the journey back to her roots as a changed person due to her experiences in the outside world.

[48] A color-coded system was used to signify which crew member could be close to the set and the actors; anybody in immediate vicinity of a scene had to wear a red wristband.

[48] Ethan Tobman, the production designer, presented Swift with reference images and ideas for the sets, and one of them was having magenta leaves on the ground, which the singer liked.

For the bonfire scene, Morgan and Prieto, gaffer Manny Tapia and key grip Donald Reynolds, sound-staged first and taped the space in the center where the magic orbs would be.

The distance was measured to the blue screen background, and taped the spots of the trees, and mapped the lighting for the set of the carnival scene.

[53] Swift performed "Willow" for the first time at the 63rd Annual Grammy Awards as part of a medley with "Cardigan" and "August", in a "dreamy" cottagecore setting featuring a moss-covered cabin in a forest, accompanied by collaborators Dessner and Jack Antonoff.

Zhang lauded Swift's vocals and the enchanted forest-themed spectacle of the set, describing her look as a "benevolent fairy princess in a kingdom of dwarves".

[58] The Washington Post ranked Swift's performance as the sixth best of the evening, and highlighted its "woodsy, mystical aesthetic" aligning with that of Folklore, with "haunted-looking trees and glittering gold lights in the background".