Growing up in the tiny village of Berkåk in Rennebu Municipality, Smeplass played piano at home and flute in her school's marching band.

However, she felt classical music was too confining, so she learned guitar and began writing her own songs, inspired by her main influence, John Mayer.

[3] 16-year-old Smeplass released her first single "Shattered", which was co-written by American singer-songwriter Melanie Fontana, after participating in Idol - Jakten på en superstjerne in 2013.

In 2016, she released the song "Hurts So Good", which was included on her debut self-titled extended play, Astrid S.[4] She also supported Troye Sivan on his European tour.

[7] She joined 16-year-old climate change activist Greta Thunberg for her Fridays For Future event in Sweden, performing a cover of "I Want to Know What Love Is" by Foreigner.

[10] In September of the same year, Smeplass announced her debut studio album, Leave It Beautiful, which was released on 16 October 2020.