Haapoja's musical background is in the new wave folk music. However, Haapoja has graduated from the Centre for Music & Technology, Sibelius Academy, and studied music with wide perspective from classical and jazz theory to contemporary music composing. In 2013 Haapoja founded the alternative hiphop collective haapoja & illmari. The collective combines electroacoustic folk and pop music, rap and urban sound art together.
During 2019-2022 Haapoja composed the music and collected soundscapes for his first solo album Unheard Landscapes, where Haapoja's global field recrodings meet electronic new wave folk music. Haapoja's main instrument is jouhikko, the Savo-Karelian bowed lyre.
Unheard Landscapes debut album's music was made also for Contemporary Circus Performance Fragile, premiered in September 2022 in Culture Centre Caisa, Helsinki. (Pic by Aleksi Hakala)
Haapoja's artistic work is a mixture of music & soundscape composing and video art. Helsingin reitit – The Routes of Helsinki is Haapoja's long term art project, which focuses on soundscapes in the boundaries between nature and the city. Haapoja's sound art piece Luotisuora - Beeline is a part of the permanent exhibition in the new Helsinki City Museum. In November 2016 the piece was installed first time in Manhattan, New York. In September 2019, all The Routes of Helsinki works were exhibited at the Sound Art Gallery Akusmata, Helsinki. Finnish national broadcasting company YLE premiered the 2010-2020 soundscape collage of The Routes of Helsinki in May 2020.
In 2021, various Haapoja's new soundscape works were presented around Finland: in EMMA Espoo Museum of Modern Art, Retretti Punkaharju Art Cave and Tytyri Lohja, in Kalevan Navetta, Seinäjoki and also in Helsinki City Museum's inner yards alongside museum's permanent exhibition.
Keitaat / Oases, created with Amanda Kauranne, is a series of audio-visual installations about Nordic nature. In 2022, Keitaat / Oases installations took place in Theaterhaus Berlin Mitte (May) and Kaustinen fmf (July). On that spring, Haapoja & Kauranne with visual artist Kira Leskinen and dance artist Gesa Piper captured and created their latest piece for the series in the Faroe Islands.