It was certified 7× Platinum by the Recording Industry Association of America (RIAA) in the United States, and it received a diamond certification from Music Canada.

In November 2000,[7] Ken Krongard, an A&R representative, invited Antonio "L.A." Reid, then head of Arista Records, to producer Peter Zizzo's Manhattan studio to hear Lavigne sing.

Her 15-minute audition "so impressed" Reid that he immediately signed her to Arista with a deal worth $1.25 million for two albums and an extra $900,000 for a publishing advance.

"[10][11] Lavigne relocated to Los Angeles, where she collaborated with songwriter and producer Clif Magness, who gave her ample creative control in the writing process.

Lavigne and Magness wrote "Losing Grip" and "Unwanted", songs that she deemed reflective of her vision for the entire album.

[12] However, Arista was not thrilled with the heavy-guitar laden songs that Lavigne was writing, prompting the label to look for other producers to match their demands.

Arista could not find the right direction for Lavigne, so the team's manager, Sandy Roberton, suggested that they work together: "Why don't you put her together with the Matrix for a couple of days?

"[14] According to member Lauren Christy, they had been listening to Lavigne's early songs and felt they contained "a Faith Hill kind of vibe".

[15] Lavigne played the Matrix a song that she had recorded and really loved, a track with sounds evocative of the rock band System of a Down.

Fortunately, prior to forming the Matrix, its members' early projects were in the pop-rock vein, so they readily figured out what Lavigne wanted to record and knew exactly what to do with her.

[16][17] With the Matrix, Lavigne recorded tracks in Decoy Studios, situated in a Los Angeles suburb known as Valley Village.

Later, on 22 July, Let Go hit record stores worldwide, and on 26 August in some parts of Europe, including the United Kingdom and Ireland.

Lavigne toured with her band—drummer Matthew Brann, bassist Mark Spicoluk, and guitarists Jesse Colburn and Evan Taubenfeld—which she had grouped after signing the deal.

[18] In the tour, she included all songs off Let Go, and cover versions of "Knockin' on Heaven's Door" by Bob Dylan and "Basket Case" by Green Day.

The tour DVD My World was released on 4 November 2003, on joint venture by Arista Records and 20th Century Fox Home Entertainment.

The DVD features the concert, a behind-the-scenes featurette, five music videos and a six-song bonus audio CD that includes an unreleased track "Why".

[15] Thought to produce wide cross-demographic appeal, however, the music video for the single features Lavigne and her band wreaking havoc in a mall, "the sort of imagery that might have grown-ups thinking 'Clean that mess up!'

[21] "I'm with You" was released in late November 2002, close to Christmas holidays to remind parents about the album to, if not to buy it themselves, to purchase it for any children in their family.

Lavigne originally wrote the song in 2001, then passed it to American singer Kelly Clarkson who recorded it for The Princess Diaries 2: Royal Engagement soundtrack.

[36] Rolling Stone magazine's music critic Pat Blashill wrote that the album "comes fully loaded with another dozen infectious hymns of Total Request angst".

[38] Christina Saraceno of AllMusic noted that Lavigne "handles a variety of styles deftly", while also complimenting her as "a capable songwriter with vocal chops".

[36] Kaj Roth of Melodic felt that Lavigne "sings lovely and some of the songs goes in the Alanis Morissette [sic] vein".

[34] For Jon Caramanica of Entertainment Weekly magazine (who gave the album a B−), "Lavigne's monochromatic debut set of unimaginative guitar rock is saved only by the earnestness of her songs.

The success of the album's commercial performance led Lavigne to be named Best New Artist at the 2002 MTV Video Music Awards.

[45] Let Go was commercially successful in the United States, gaining praise from Entertainment Weekly magazine as one of the biggest pop debut albums of 2002.

During this time also, Lavigne received much media coverage due to her nominations at the 2003 Grammy Awards and for embarking on her first North American tour.

[72] In Australia, Let Go had been certified seven-times platinum by the Australian Recording Industry Association in 2003, based on the sales of over 490,000 units from wholesalers to retailers.

[31] Pitchfork observed in 2018 that Let Go "boasts a handful of genre-changing smashes and mood swings that’d put a high school sophomore to shame.

Lavigne told Rolling Stone in 2003 that "Arista was drop-dead shit afraid that I would come out with a whole album" sounding like these songs;[12] they wanted her to go in a more radio-friendly direction.

For this purpose, Arista assigned her the production team the Matrix, who wrote the pop rock song "Complicated" with minor help from Lavigne.