Vartiainen rose to publicity by winning the Finnish talent show Popstars in October 2002 with Susanna Korvala, Ushma Karnani (currently Olava) and Jonna Pirinen.

In late March 2010, Jenni Vartiainen released her second studio album Seili, after the arrival of its gold-selling debut single "En haluu kuolla tänä yönä".

Vartiainen's third studio album, Terra, released in October 2013, debuted at number one and sold triple platinum with over 62,000 copies.

She was about to travel abroad, but her plans changed as she saw an advertisement of Popstars, the first Finnish season of the New Zealand-based casting show format.

[8] Along with Ushma Karnani (currently Olava), Susanna Korvala and Jonna Pirinen, she won the contest in October and the quartet formed the band Gimmel.

[8] In the 2007 interview with City, she said that Risto Asikainen, who wrote songs for the band, did not allow the trio inside the studio so that "they would not boss around".

[8] In an August 2010 interview with Me Naiset, Vartiainen said that she also learned from Gimmel "how it feels like when records don't sell and there are only ten people at a gig", adding that "an artist has to develop all the time and work like a maniac".

The production of her debut album together with producer Jukka Immonen took so long that Vartiainen ran out of money, which led her to ask for cleaning jobs at Warner studios and ultimately she worked at a company, processing consumer complaints.

[35] "Dumbfounded" by her success with Seili, she said in an interview at the Emma Awards that "the way music starts to live its completely own life in the audience after being produced", makes her feel humble.

[37] Amid her busy concert tour around Finland in the spring of 2011, she denied some tabloid rumors that she would have canceled interviews due to stress and exhaustion.

[44] In late January 2012, Vartiainen was about to perform briefly at a fundraising concert for the presidential campaign of the Green League's Pekka Haavisto, but she was forced to cancel due to high fever and gastroenteritis.

[46] Jenni Vartiainen, who is known for keeping a very low profile on her private life,[9] was reported on 28 March 2009 to have started a cohabitation with her producer Jukka Immonen.

[50] During the summer of 2011, Vartiainen was a subject of pregnancy rumors in the media, due to her loose concert outfits, a slightly more rounded belly and the post-summer break the length of which was not specified.