Arnaert was born on 13 September 1979, in Heuvelland, Belgium. She has two siblings: Anne Arnaert and Kaat Arnaert, has been a featured singer with the Belgian bands Sutrastore and Tommigun .
According to Alex Callier, when the band was looking for new lead singer, he asked Geike "It is almost schoolbreak, in September you'll be 18 years old, do you want to be our singer?". She immediately said: "Yes, that's OK!".
After more than 10 years in the band, on 10 October 2008, Arnaert announced she would leave Hooverphonic by the end of the year to pursue her solo career. Geike's last concert with Hooverphonic was on 13 December of that year, in Tele-Club, Ekaterinburg, Russia. The reason to leave, as she stated in the press, was "simple and without (band) troubles. I wish other musical and artistic projects and I want to concentrate on my own music career". Three years later, however, in a comeback interview for her new solo album, she commented on her departure: "There were several reasons. As I grew older and wiser, I developed my own character and my own artistic ideas. I tried to bring that out but there were the others (Alex Callier and Raymond Geerts) who were not open to it. The roles were fixed, and mine was singing and staying silent and beautiful. I own ideas, and ten years seems long enough to go into the trip of someone else. Moreover, it was confrontational to note that men with whom I had to work and that I saw as a kind of brothers, saw me as something else. Even outside the band, I remember Mushroom of Massive Attack insisted that I contacted him. But when it turned out that I had a boyfriend, it was suddenly no longer needed. Let me also say that the humor on the tour bus was not always sophisticated and sometimes just disrespectful. Men do not understand that you are a woman sometimes feeling lonely or targeted".
In February 2016, 7 years after her last performance with the band, Geike performed "Mad About You" together with Hooverphonic, for a special event of the Radio2 in Belgium. According to Callier, that was a "once-off" cooperation.
In 2010 Geike was brought together with Spinvis to work on the soundtrack of Breath (original title: Adem), a Belgian film about young people who suffer from mucovisidosis. Having written more material than needed for the film, they released a record. They called themselves Dorleac for the occasion.
In 2011 Geike released her first solo album, "For The Beauty Of Confusion."
She recorded the historical French song "Le temps des cerises" with the legendary singer-songwriter and entertainer Bobbejaan Schoepen for his 2008 album "Bobbejaan", his first album in 35 years. A music video for the song was also released.
Geike has also sung as a guest vocalist for various artists such as Ozark Henry, Flip Kowlier and Tom Helsen.
Geike contributed vocals to "Mijn Leven" (My Life), the final single by Belgian rapper Vijvenveertig (Andy Sierens). The song was recorded two weeks before Sierens died of cancer.2011 – For the Beauty of Confusion
2011 – "Rope Dancer"
2011 – "Unlock"
2011 – "Blinded"
2010 – Dorléac
2010 – "Tommy and the Whale"
"Le temps des cerises" - Bobbejaan Schoepen & Geike Arnaert (2008)
"Home" - Tom Helsen feat. Geike Arnaert (2008)
"Bjistje In Min Uoft" - Flip Kowlier feat. Geike Arnaert (2004)
"The Wild Rose" - Sioen & Geike Arnaert (live duet)
"Close watch" - Live Duet with Daan
"Mijn Leven" - Vijvenveertig feat. Geike Arnaert (2009)
"Strange Lit Star" - Ozark Henry feat. Geike Arnaert (2002)