She subsequently signed with Australian independent label Shock Records, and released her self-titled debut album Ricki-Lee (2005), which produced the top-ten hits "Hell No!"

The following year, Coulter became a member of the Australian pop girl group Young Divas, before leaving in early 2007 to resume her solo career.

Several months later, Coulter's ability to sing was discovered by her mother, who overheard her in her bedroom, which led to her performing at gigs in the Gold Coast and Brisbane areas with live bands.

[12] The following year, Coulter successfully auditioned for the first season of Popstars Live and progressed to the top sixty round of the competition but was part of the first group of performers who were sent home.

[12] Later that same year, Coulter successfully auditioned for the second season of Australian Idol, singing En Vogue's "Don't Let Go (Love)", and progressed through to the semi-finals.

[12] Throughout the season, Coulter was regarded as a favourite to win the competition because of her performances of Michael Jackson's "Don't Stop 'til You Get Enough", Tina Turner's version of "Proud Mary" and Whitney Houston's "I Have Nothing".

[12] Following her elimination, "newspapers ran the story as front-page news and Coulter herself couldn't quite hide the anger and disappointment she plainly felt".

[22] Coulter collaborated with several producers and songwriters on the album, including Audius Mtawarira, Israel Cruz, Nitty, Jarrad Rogers and Kara DioGuardi, among others.

[24] That same year, Coulter joined forces with previous Australian Idol contestants Paulini, Emily Williams and Kate DeAraugo to be part of the all-girl singing project called Young Divas.

[25] Young Divas released a cover version of Donna Summer's single "This Time I Know It's for Real" in May 2006, through Sony BMG, to promote tickets for the tour.

[28][31] Their commercial success prompted the release of a debut album of classic disco and pop covers titled, Young Divas, on 27 November 2006, establishing themselves as an official group.

[28] In February 2007, it was announced that Young Divas had pulled out of their scheduled national tour supporting Irish boy band Westlife, because Coulter had headed overseas to work on her second solo album.

[22] Coulter worked with several producers and songwriters on the album, including KNS, David Gamson, Marc Nelkin, Vince Pizzinga, Andrew De Sylva, Mtawarira and Glenn Cunningham, among others.

[44] Her version of Swedish recording artist Agnes Carlsson's "Love Is All Around" was released as the second single from Brand New Day in November 2007, and peaked at number five.

[22][45] On 18 November 2007, Coulter performed at the first Fluffy Festival in Brisbane alongside acts such as Mr Timothy, Slinkee Minx, Potbelleez, TV Rock, Seany B and Vandalism.

[67][68][69] Throughout 2010, Coulter put her music career on hold as she took on a full-time position as a breakfast radio presenter for Sydney's Nova 96.9, alongside Merrick Watts and Scott Dooley.

[60] She later stated that after attending a Thirty Seconds to Mars concert in Melbourne and rewatching Michael Jackson's Dangerous Tour DVD, she was inspired to perform again.

[67] Following the release of her single "Raining Diamonds" in October 2011, it was revealed that Coulter had signed a record deal with major label EMI Music Australia.

[92][93] The "lulling, soft ballad" marks a departure from Coulter's previous dance releases, and is lyrically about "redemption and it never being too late to right our wrongs and start again.

[100] The tour featured Coulter performing songs from the film A Star Is Born (2018) and from her time on Australian Idol (2004), as well as her greatest hits as a solo artist and with the Young Divas.

[110][111] Guy Blackman of The Age noted that Coulter's self-titled debut album, Ricki-Lee (2005), "is an infectious collection of R&B-tinged pop tunes that takes a step beyond the usual Idol fodder".

[112] Her second album, Brand New Day (2007), features upbeat dance songs,[111] with elements of disco, reggae, 40s swing music, 70s jazz pop and motown.

[124] In February 2008, she was a mentor on the third season of the celebrity singing show, It Takes Two, and was partnered with professional golfer and tennis player Scott Draper.

[127][128][129] Coulter became a mentor for the first season of The Voice Australia in 2012, and paired up with coach Seal to prepare the contestants in his team for the show's battle rounds.

[133] Filmed in New Zealand's South Island in April 2015, the show featured nine ordinary Australians taking on challenges to raise money and awareness for the CanDo4Kids charity.

[136] In 2022, it was announced that Coulter would be joining the Seven Network reboot of Australian Idol as a co-host alongside Scott Tweedie, after a thirteen-year hiatus from the show.

[137][138] Coulter made her debut as a radio presenter in January 2008, joining Brisbane's B105 FM breakfast team, alongside Labrat, Stav and Camilla.

[147] In May 2012, she became the face of the 2012 Woolworths Supermarkets Earn & Learn program, which aims at delivering "millions of dollars worth of educational resources" to primary and secondary schools in Australia.

[151][152] In 2008, Coulter became the face of Jeans for Genes Day in Australia, a charity fundraising event organised by the Children's Medical Research Institute which sponsors investigation into childhood genetic diseases.

[160] In an interview with Herald Sun's Jonathan Moran, three years after the marriage ended, Coulter revealed that she had experienced depression during her relationship with Babbington.