[19] At age 12, McKee's mother gave a demonstration CD featuring her singing Bette Midler and Fiona Apple songs to a friend of hers who is the co-founder of the Sub Pop label, Jonathan Poneman.

[20] Her debut album Trouble was recorded across a period of two years by producers Bob Power and Rob Cavallo,[21][22] and commercially released on September 28, 2004.

[2] Reprise Records was unsure on how to sell McKee, so the label settled a partnership with internet radio website LAUNCHcast, which would promote the lead single "Somebody".

"Somebody" soon became one of the most played tracks on the website, and its popularity with young females led to a strategy where McKee would be a subversive alternative to the teen pop demographic.

[23] "Somebody" was performed on Jimmy Kimmel Live!, included in the motion picture Win a Date with Tad Hamilton!, and had a music video featured on MTV's Buzzworthy and VH1's You Oughta Know.

[24] Trouble received positive reviews in Blender, Nylon, The Los Angeles Times, and Teen People, but was commercially unsuccessful.

[21][26] She lived in poverty, without hot water, a cell phone, or a car[27] while spending many hours in the recording studio, learning how to use Pro Tools and crafting new songs alongside Elliott Yamin and Leighton Meester.

In 2009, McKee was introduced to music producer Dr. Luke by her manager Josh Abraham, who signed her to his production label Prescription Songs.

[31][32] McKee also co-wrote two more chart-toppers for Perry, "Part of Me" and "Roar" as well as four other songs which hit number one on either the Hot 100 or the UK Singles Chart, Britney Spears' "Hold It Against Me", Taio Cruz's "Dynamite", Rita Ora's "How We Do (Party)", and Cheryl's "I Don't Care".

At the Billboard Music Awards 2015, McKee revealed in an interview that Charlie Puth, with whom she had previously worked on her song "California Winter", had co-written her next single, which she also said would be released in the next week.

For Christmas, McKee released a special called "California Winter Extravaganza" on her YouTube account on December 16, which features Ferras, Sarah Hudson, Lindsey Stirling, Todrick Hall, Karmin, Eden xo, Paper Pilots, and Bridget Marquardt.

"Doves Cry" is perfection and I know I could never even hope to touch his brilliance, but in his passing, I realized how much this song really means to me, and was inspired to pay homage to the late, great, genius who taught me to take musical risks, to act my age and not my shoe size, and how to get through this thing called life".

[48] On June 21, 2016, McKee released a remix for "I Want It All" featuring Vicetonr as the third single from the EP and published a music video for the original version on her VEVO account.

[49] In September 2016, in collaboration with Quest Nutrition brand, McKee released the video for the song "Stud Muffin" inspired by the movie Grease.

[58] During 2022 and 2023, McKee re-recorded songs that were intended for her 2013 album with Epic Records, after joining TikTok and receiving from her followers many questions about the scrapped project, that have been recurrent on social networks and internet forums over the years.

[59][12] For some interviews, McKee talked about finding an internet forum which had a thread to about 500 pages discussing that era and songs corespondent,[59][12][60] where it was found to have been titled Hot City.

"[62] In the time between "SLAY" and "Jenny's Got a Boyfriend," two other singles were released by McKee, "Hot City"[63] and "Don't Get Mad Get Famous,"[64] attached to the 2013 era and present in the rerecorded album.

[65][13] "Forever 21," another track sung in 2013 on Karmin's Pulses Tour[60] that also leaked online,[65] and has been since promptly hyped by McKee's fans too,[12] was offered as a ready-to-download track during the preorder for Hot City, exclusively through Apple Music,[67] whilst it was revealed the album version for "Don't Get Mad Get Famous," released earlier as a solo single,[64] features Canadian artist Sophie Powers.

"[12] She informed too that Epic Records, noticed by her as being nowadays "all different people there now from where [she] signed to," has not made any objection to her independent release, but rather have been "very cooperative and cool" to her, adding that "now we're kinda partnering on [the album].

[74] To promote Hot City, McKee will serve as a supporting act to most dates of Canadian artist Kiesza's Dancing and Crying Tour, with concerts to be held on theatres across the Pacific Coast of the United States and Canada during October 2024.

[78] On October 9, 2024, McKee made available for pre-order both CD and vinyl formats off Hot City, the former through her official webstore,[79] and the latter through Graffiti Records website.

[81] On Halloween's Eve of 2024, McKee released an EP to her 2013 single, "Sleepwalker," including a remix featuring American indie artist Mothica.

The EP, named Sleepwalker (Resurrected), features also five previously released McKee's collaborations under collective musician band project LVCRFT.

[82] Following that, on December 18, 2024, a Christmas EP titled after her 2014 single, "California Winter," featuring the track in its original form and also as a re-recorded duet with American singer, actor, and comedian Matt Rogers, plus other four Christmas tracks, including a cover of Canadian singer and songwriter Leonard Cohen's 1984 single and posterior signature hit, "Hallelujah," got released on streaming music services.

"[84] McKee has cited Mariah Carey, Madonna, Tina Turner, Blondie, Michael Jackson, Whitney Houston, and Prince as major influences.