Jessica Ellen Cornish was born on 27 March 1988 in Redbridge, London, to Rose (née Archer) and Stephen Cornish. She was educated at Mayfield High School in Redbridge. This area was historically part of Essex and Jessie J refers to herself as an Essex girl. She attended Colin’s Performing Arts School and as an 11-year-old she was cast in Andrew Lloyd Webber’s West End production of Whistle Down the Wind. She subsequently joined the National Youth Music Theatre and appeared in their 2002 production of The Late Sleepers.

Cornish has two elder sisters, who were both head girls at school. Unlike her academic sisters, Cornish has stated she was “never really that good at anything”. She said, “At school they were like ‘oh, you’re a Cornish girl’ and they kind of expected me to be the same as my sisters. Give me something to draw or an outfit to pick for someone, or hair, make-up, acting, write a song, I’m fine with it, but anything to do with sums – it was never my thing.” She also said she never based her intelligence on her exam results. She also said she was always good at singing and it was her “thing”. In 2003, at age 15, she won Best Pop Singer in the TV show Britain’s Brilliant Prodigies, performing as Jessica Cornish. At the age of 16 she began studying at the BRIT School and at 17 she joined a girl group named Soul Deep. She graduated in the class of 2006 along with singers Adele and Leona Lewis. She claims she suffered a ‘minor stroke at 18.’

Jessie J began recording her debut studio album in 2005 and it was completed on 19 January 2011. She revealed that “Big White Room” would be on the album and was written from an experience she had when she was aged 11, although she wrote the song at age 17, in the hospital, where a ward mate, a little boy, died. Jessie J says the album’s title track, “Who You Are”, is one of her proudest creations, she said the song is a “positive role model for young people” and “I always say that I’m half-artist, half-therapist”. The song was written in 2005, when she just moved to Los Angeles, and was going through a very lonely difficult moment. A song called “Sexy Silk”, which appears on the Easy A soundtrack, was originally going to be her first single. However, in late 2010 Jessie J released her first single, “Do It Like a Dude” which was co-written with George Astasio, Tj Normandin, Jason Pebworth, Jon Shave, Kyle Abrahams and Peter Ighile. Originally, she wrote the song with Rihanna in mind because “Rude Boy” was released at the time, partly inspiring the song. She then sent the song to her label, Island Records, before sending it to Rihanna’s management. Island insisted the song become Jessie J’s first single. The single gained positive reception from critics. The single charted at number two on the UK Singles Chart. Her follow-up single “Price Tag” was released in late January 2011. It was written by Jessie J, Dr. Luke, Claude Kelly, and B.o.B and peaked at number one on the UK Singles Chart. “Price Tag” was released in the US on 1 February 2011 and peaked at 23 on the Billboard Hot 100. “Price Tag” also charted at number-one in New Zealand and Ireland and is the most successful online video J has released. Her first American television appearance was as the musical guest on NBC’s Saturday Night Live on 12 March 2011.

On 25 February 2011 her debut album, Who You Are, was released. The album first entered the UK Albums Chart on 6 March 2011 where it charted at number two. The album charted into the top ten in a number of countries and number 11 in the US. After the release she went on to release a third single from the album, “Nobody’s Perfect”. MTV reported that the single is, so far, only confirmed for release in the United Kingdom. The album’s fourth single was “Who’s Laughing Now”. “Domino” was her second US single. The Dr. Luke-produced track was sent to mainstream radio on 6 September 2011. With the success of Who You Are in North America, Jessie was chosen to tour as the opening act for American pop artist Katy Perry’s California Dreams Tour in 2011 but pulled out after breaking her foot in rehearsals. Jessie J served as the house artist at the 2011 MTV Video Music Awards, performing several of her original songs along with covers around commercial breaks.

On 12 June 2011, at the Summertime Ball held at Wembley Stadium, London, Jessie ruptured several tendons in her foot during rehearsals, and performed her set the following day while sitting on a gilded throne. For her appearance at Glastonbury Festival 2011 on 25 June 2011, she performed on the throne again, stating that her doctor had told her not to perform with her broken foot which would take six weeks to heal. Jessie J was scheduled to play at several festivals throughout the summer, however it was reported on 1 July 2011 that she would not be able to attend T in the Park, T4 on the Beach, Wembley:Orange, iTunes Festival, Lovebox, and Oxegen due to the injuries to her foot. Her record label released an official statement on 30 June 2011 that under strict orders from her doctor, she would not be able to perform for a number of weeks so that she could recuperate properly. She returned to the concert circuit in late August, including sets at the V Festival and The Big Chill. At the 2011 MTV VMA’s she was still in a cast and using the throne.

James Morrison’s third studio album, The Awakening features a collaboration with Jessie J called “Up”, the song was released as a single on 16 November 2011. Jessie J re-released Who You Are on 9 November 2011, featuring the regular tracks plus “Domino”. “Domino” topped the UK charts and became her first top 10 hit in the US, following the success of “Price Tag”. While in Australia for the Oceania leg of her Heartbeat tour in support of Who You Are, an interview on a TV talk show ended with her being sawed in half by magician Sam Powers in his thin model sawing illusion. At the 2012 Brit Awards on 21 February, Jessie J received two Brit Award nominations, Best British Female Artist, and Best British Single (“Price Tag”).

Asked about her bisexuality in an interview on the “In Demand” radio show on 3 March 2011, Jessie J stated, “I’ve never denied it. Whoopie doo guys, yes, I’ve dated girls and I’ve dated boys – get over it.” Sophie Wilkinson of The Guardian argued that Jessie J’s sexuality was valuable to young teens, especially for young girls unsure of themselves because of their sexuality and identity, to feel “that this does happen and this is normal.” In April 2014, Jessie J renounced her bisexuality, stating, “For me, it was a phase. But I’m not saying bisexuality is a phase for everybody.” Laura Kay of The Guardian said although she would never deny anyone the right to define their own sexuality, Jessie J renouncing her bisexuality “feels like such a loss for young gay or questioning people who look up to her”, and wondered if the wrong message might have been sent because phase is “an unhelpful term as this is an idea that gay people find themselves constantly battling against.”

In early 2011, Jessie J suffered a panic attack on stage after she was forced to perform in the dark. “I did a gig recently and had a panic attack on stage,” she said. “The night was called ‘Black Out’ and I had to perform in the dark. I asked them to turn on the lights and they didn’t. I was onstage in pitch black and, because I couldn’t see anything, I started to panic. It was awful.”

Jessie J has appeared on the major UK charity telethons, Children in Need and Comic Relief, both broadcast on the BBC. She confirmed on 2 August 2011 that she would be shaving her hair off for charity in 2012. Speaking via her official Twitter account she said: “It’s hair, It will grow back. Even if it takes 2 years, if it saves lives it’s worth it. Even if its 1 life that’s something.” On 15 March 2013, Jessie’s head was shaved live during Red Nose Day 2013, helping to raise money for Comic Relief.

In November 2011, Jessie J performed “Nobody’s Perfect” at the charity concert Children in Need Rocks Manchester held at the Manchester Arena to raise money for Children in Need 2011. Jessie J is a supporter of UK children’s charity Believe in Magic, a charity that grants wishes to terminally ill children across the UK. In July 2012 she performed “Laserlight” on stage with a 7-year-old fan, leukaemia sufferer Daniel Sullivan, who would pass away four months later.

With featured artist, David Guetta, Jessie J released the sixth single, “Laserlight”, from her debut album on 4 May 2012. In the United Kingdom, the song debuted at number twenty-six on the UK Singles Chart on the chart issue dated 21 April 2012. The following week the song climbed twenty-one positions to number five, making it her sixth top ten single from one album. With the charting success, she became the first UK female solo artist to achieve six top-ten singles from a single studio album. The achievement was compared with Lady Gaga, Katy Perry, Michael Jackson and boy band Take That, recording artists who previously broke the same record.

On 4 June 2012, Jessie appeared at the Diamond Jubilee Concert for Queen Elizabeth II, performing a duet with will.i.am. Together, they performed “I Gotta Feeling”, a song she previously recorded with the other four coaches of the televised singing competition, The Voice. She later sang her international hit, “Domino”. On 12 August 2012 she performed “Price Tag”, “Written in the Stars”, “Dynamite”, and “You Should Be Dancing” with Tinie Tempah and Taio Cruz, and “We Will Rock You” with Queen at the Closing Ceremony of the 2012 Olympic Games in London. Jessie J was a coach on the BBC One programme The Voice UK for its first two series in 2012 and 2013.

On 31 January 2012, Jessie J announced that she had begun recording her second studio album. She also stated that she hoped to collaborate with many artists that year, possibly including some of her fellow coaches on The Voice. It was revealed that she worked in the studio with CeeLo Green after he contacted her on Twitter. Jessie has also revealed on Twitter that she worked with Diane Warren and co-author of her song “Price Tag”, Claude Kelly.

Via microblogging website Twitter, Jessie J announced her first arena tour, called Nice to Meet You Tour (later renamed Alive Tour due to the release of her second studio album titled Alive), which began on 15 October 2013 and concluded on 8 February 2014. “Wild” was released as the lead single from Alive and was a top 5 hit in both the United Kingdom and Australia. Other singles released from the album included “It’s My Party” and “Thunder”. Jessie also featured on DJ Cassidy’s debut single “Calling All Hearts”, along with Canadian singer Robin Thicke.

Her third studio album Sweet Talker was released on 13 October 2014 in the UK, where it peaked at number 5. “Bang Bang” recorded with Ariana Grande and Nicki Minaj serves as the first single from the album. The song reached number one on the UK Singles Chart, becoming her third number one and seventh top five single in the UK. “Bang Bang” debuted on the US Billboard Hot 100 at number 6, making it the second highest new entry of 2014 on the chart. The song became Jessie J’s second top 10 single in the US, after her previous single “Domino”, and eventually peaked at number 3. In 2015, she became the judge and mentor of The Voice Australia replacing will.i.am. In the nominations for the 2016 Brit Awards, Jessie J’s 2015 single “Flashlight” (from the soundtrack to the film Pitch Perfect 2) was among the nominees for Best British Video. In January 2015 she began the Sweet Talker Tour to promote the album.

In 2014, Jessie J relocated from London to Los Angeles, California. She cited work opportunities and dissatisfaction with the level of focus in the UK on her personal life rather than on her singing, saying, “In America they see me as a singer whereas here I feel that people don’t appreciate my voice.”

In November 2014, she started dating American singer Luke James. The couple ended their relationship in October 2015. It’s unclear whether the pair rekindled their relationship, but they went on to perform together a couple of times. Since 2018, she and American actor Channing Tatum have been in an on-again, off-again relationship.

In 2016, Jessie J joined the cast of voices for Ice Age: Collision Course singing the movie’s theme song “My Superstar” (written by Alexander Geringas and Nikki Leonti) featuring Tha Vill. The song was eventually not released as a single and was not included in the soundtrack.

On 11 August 2017, Jessie J released a new single, “Real Deal”, for M&M’s advertising campaign. On 12 September, she announced her fourth album R.O.S.E. and the single “Think About That”, which was released on 15 September 2017 as the album’s lead single. Four further songs from R.O.S.E. were then released, with “Think About That” representing realization. “Not My Ex”, was released as its second single on 6 October 2017 and represents obsession and the third single “Queen” was released on 17 November 2017, representing empowerment. In October 2017, Jessie J began her R.O.S.E. tour across Europe and the US to promote the upcoming album.

In January 2018, she appeared on the sixth season of the China’s singing competition I Am a Singer. Jessie J won the competition, making history as the first international singer to win the season in the show’s six-year history, accompanying with the record of having topped number-one performances in five out of the first ten (of eleven) elimination rounds. The series cast also included two of the six other initial singers (singers entering on the first week of the competition with the exemption of participating Breakout rounds) Angela Chang and Wang Feng, and also her closest rival and runner-up for the season, Hua Chenyu, who would later went on to win the eighth season held two years later.

In May 2018 her fourth studio album R.O.S.E. was released. The album was released as four EPs titled Realisations, Obsessions, Sex, and Empowerment, creating an acronym for “R.O.S.E.” The album moved away from the pop sound heard in much of her past music, instead taking on an R&B style. In September 2018, Jessie J announced her first Christmas album titled This Christmas Day, which was released on 26 October 2018. In December 2018, Jessie J confirmed that she would be appearing as a coach on The Voice Kids UK alongside Pixie Lott, Danny Jones and will.i.am for its third series. She also stated in an Instagram Live that she wants to write new pop/soul songs. In April 2019 Jessie began touring festivals across Europe and Asia. She announced via Instagram that the tour is called The Lasty Tour, in honor of her close friend and bodyguard Dave Last “Lasty” who died in December 2018.