Foureira began her music career as a member of the girl group Mystique. She was discovered by Andreas Giatrakos, and the group also consisted of Alkmini Chatzigianni and Maria Makri. They released their debut single “Se alli selida” in 2007, and later achieved success with the single “Min kaneis pos de thymasai” featuring Greek hip hop group NEVMA the following year. They later broke up in 2009.

After the break up of Mystique in 2009, Foureira signed a solo contract with Universal Music Greece, the label which Mystique was signed to as well. She later appeared on the charity program Just the Two of Us, hosted by Mega Channel. She managed to win first place along with singer Panagiotis Petrakis. Foureira released her self-titled debut studio album in December 2010, which went on to become certified platinum in Greece. Afterwards, she signed with Minos EMI. Her second album Ti poniro mou zitas was released in 2012, while her third Anemos agapis was released in 2014. From 2015 to 2016, she starred as Sofia in the musical Barbarella: the 80’s Musical in Athens, alongside other Greek pop stars such as Ivi Adamou and Katy Garbi. Following the release of Anemos agapis, she left Minos EMI and signed with Panik Records. She was a judge on season three of the Greek version of So You Think You Can Dance. Her fourth studio album Vasilissa was released in 2017.

Foureira has made several attempts to represent Greece in the Eurovision Song Contest. In 2010, she took part in the Greek national final for the Eurovision Song Contest 2010 with Manos Pyrovolakis, performing the song “Kivotos tou Noe”. They placed second behind Giorgos Alkaios. In 2013, she performed “Wild Dances” with Ruslana at Eurosong 2013 – a MAD show. She later considered taking part in Eurosong 2015 – NERIT & MAD show, but ultimately did not. She once again attempted to represent Greece in the Eurovision Song Contest 2016 with the song “Come Tiki Tam”, but was rejected by Hellenic Broadcasting Corporation (ERT). In 2017, she was rejected by the broadcaster for the Eurovision Song Contest 2017 once again.

Since the beginning of her career, Foureira’s ancestral origins have garnered intense speculation from the Greek media. As a member of Mystique, she claimed to be Brazilian. However, she later began claiming that her father was from Athens and her mother from Ioannina, although she had some Mexican ancestry as well. In 2010, reports of Foureira attempting to naturalise as a Greek citizen further increased speculation regarding her origins.

In 2013, it was reported by the Greek media that Foureira was born in Albania and that her birth name was Entela Fureraj. Foureira did not comment on the reports until 2014, when she confirmed them. She claimed that she did not reveal her origin in order to be accepted in the music industry in Greece. She continued claiming she never understood the issue, since she always felt Greek and she has received only Greek education. Andreas Giatrakos, who discovered Foureira and recruited her to join Mystique, later stated that he wanted Foureira to be proud of her origin and would not have rejected her if he knew she was born in Albania. She was even reluctant to declare herself a Northern Epirote, because this would possibly harm her career. She simply declared that she was born in Albania.

In February 2018, it was confirmed that Foureira would represent Cyprus in the Eurovision Song Contest 2018 with the song “Fuego”. The song was composed by Greek–Swedish songwriter Alex Papaconstantinou. On 8 May 2018, she qualified from the first semi–final to the grand final. In the final held on 12 May 2018, she finished as the runner–up to winner Netta from Israel, having received the fifth most votes from the international juries and the second most votes from the public televoting process; this marked Cyprus’ best Eurovision placement in history.

On 17 May 2019, Eleni released her first international project, an extended play titled Gypsy Woman, which includes the song “El Ritmo Psicodelico” as the lead single. To further promote her studio project, she embarked on a European tour in various cities in Greece, Spain, and the United Kingdom. Around the same time, during the Host Broadcast press conference of the Eurovision Song Contest 2019, Foureira was announced as one of the four artists from previous contests that will perform at the finals of the show, where performed the 2007 runner–up Verka Serduchka’s song “Dancing Lasha Tumbai”. Throughout the rest of the year, she mostly took part in collaborations with artists such as Kaan and Snoop Dogg, and Claydee. In March 2020, she released the electropop and R&B single Yayo. In June, she released a Greek single “Temperatura”, which was later accompanied with a Spanish version.