Her second album, Under My Skin (2004), became Lavigne's first to reach the top of the Billboard 200 chart in the United States, going on to sell 10 million copies worldwide.

[17] Mark Jowett, co-founder of a Canadian management firm, Nettwerk, received a copy of Lavigne's karaoke performances recorded in her parents' basement.

[17] In November 2000,[11] Ken Krongard, an A&R representative, invited Antonio "L.A." Reid, then head of Arista Records, to Zizzo's Manhattan studio to hear Lavigne sing.

Sarubin told HitQuarters that they initially struggled; although early collaborations with songwriter-producers including Sabelle Breer, Curt Frasca and Peter Zizzo resulted in some good songs, they did not match her or her voice.

It was only when Lavigne went to Los Angeles in May 2001 and created two songs with the Matrix production team—including "Complicated", later released as her debut single—that the record company felt she had made a major breakthrough.

The International Federation of the Phonographic Industry ranked "Girlfriend" as the most-downloaded track worldwide in 2007, selling 7.3 million copies, including the versions recorded in eight different languages.

[80] The lead single from Lavigne's fifth album, "Here's to Never Growing Up" (produced by Martin Johnson of the band Boys Like Girls), was released in April 2013[81] and reached top 20 positions on the Billboard Hot 100, Australia and the UK.

[93][94] The album reached the top ten in Australia, Austria, Canada, Germany, Italy, Japan, Switzerland and the United Kingdom, and peaked at number thirteen on the U.S.

[104] On July 16, 2021, Willow Smith released her fourth album, titled Lately I Feel Everything, with one of the tracks, "Grow", featuring Avril Lavigne and Travis Barker.

[114][115] On September 13, 2022, Lavigne attended, presented and performed at the 15th Annual Academy of Country Music (ACM) Honors at the Ryman Auditorium in Nashville, Tennessee.

[119] While promoting "I'm a Mess", Lavigne confirmed she was working on her eighth album with John Feldmann, Barker, Yungblud and Alex Gaskarth of band All Time Low.

[121] On June 9, 2023, Lavigne did a live collaborative performance with country music artist Miranda Lambert during the 2023 CMA Fest at Nissan Stadium in Nashville, Tennessee.

[145][146][147] The album Under My Skin, was noticeably darker musically, with heavier production that showcased ballads and rocker songs which incorporated a more post-grunge sound that verged on nu metal,[148][149][150][151] while keeping pop punk power chord influences.

The songs were described as sounding like Toni Basil cheerleading for Blink-182,[157] with Lavigne praised for her ability to combine bubblegum pop melodies with punk rock riffs.

[168][169][170][171] On a review for Lavigne's song Sk8er Boi, Pat Blashill of Rolling Stone described her voice as "equal parts baby girl and husky siren".

"[182] Shortly after that, Tommy Dunbar, founder of the band the Rubinoos, sued Lavigne, her publishing company, and Lukasz "Dr. Luke" Gottwald for allegedly stealing parts of "I Wanna Be Your Boyfriend" for her song "Girlfriend".

[186] Lavigne's earlier influences came from country music acts such as Garth Brooks, the Chicks, and Shania Twain,[175][14] and alternative singer-songwriters such as Alanis Morissette, Lisa Loeb, Natalie Imbruglia, and Janis Joplin.

Lavigne's close friend and first guitarist, Evan Taubenfeld, said: "It's a very touchy subject to a lot of people, but the point is that Avril isn't punk, but she never really pretended to claim to come from that scene.

[198] Lavigne eventually took on a more gothic style as she began her second album, Under My Skin, trading her skating outfits for black tutus[196] and developing an image marked by angst.

She dyed her hair blonde with a pink streak, wore feminine outfits,[200] including "tight jeans and heels",[63] and modelled for magazines such as Harper's Bazaar.

"[202] Lavigne is considered a highlight in the pop-punk and alternative rock scene, since she helped pave the way for the success of female-driven punk-influenced pop artists such as Paramore, Skye Sweetnam, Fefe Dobson, Lillix, Kelly Osbourne, Krystal Meyers, Tonight Alive, Courage My Love, and Hey Monday.

[214][215][216][217] Lavigne has influenced a wide array of musical artists, including acts such as Tramp Stamps,[218] Bebe Rexha,[219] Billie Eilish,[220] Courage My Love,[221] 5 Seconds of Summer,[222] Yungblud,[223] Maggie Lindemann,[224] Tonight Alive,[225][226] Willow Smith,[227] Amanda Palmer,[228] Misono,[229] Rina Sawayama,[230] Hey Monday,[231] Grey,[232] Ed Sheeran,[233] Kailee Morgue,[234] Charli XCX,[235][236] MercyMe,[237] Palberta,[238] Yeule,[239][240][241] Olivia Rodrigo,[242][243] and Kirstin Maldonado.

[245] Lavigne has also had a significant influence on indie rock singer-songwriters such as Pale Waves,[246][247][248] Graace,[249] Phoebe Bridgers,[250][251] Soccer Mommy,[252] Ethel Cain,[253] Snail Mail, and Liz Phair.

She collaborated with artist Camilla d'Errico and writer Joshua Dysart on the manga, which was about a shy girl named Hana who, upon meeting her hero, Lavigne, learned to overcome her fears.

[265][260] Lavigne achieved a Guinness World Record as being the youngest female solo artist to top the UK album chart, on January 11, 2003, at the age of 18 years and 106 days.

[288] In September 2011, Lavigne appeared on the Hub Network's televised singing competition Majors & Minors as a guest mentor alongside other singers, including Adam Lambert and Leona Lewis.

[289][290] Kohl's describes Abbey Dawn as a "juniors lifestyle brand",[55] which incorporates skull, zebra, and star patterns, purples and "hot pinks and blacks".

[304] Lavigne has been involved with many charities, including Make Some Noise, Amnesty International, Erase MS, AmericanCPR.org, Special Olympics, Camp Will-a-Way, Music Clearing Minefields, US Campaign for Burma, Make-A-Wish Foundation and War Child.

[309] In 2010, Lavigne was one of several artists who contributed their voices to a cover of K'naan's "Wavin' Flag" as a benefit single to help raise money for several charity organizations related to the 2010 Haiti earthquake.

[324][325] Lavigne appeared in the June/July cover story for Inked magazine, where she discussed and showed off her tattoos, including an "Abbey Dawn" on her left forearm and an "XXV" and star on her right.