Goss was born in Los Angeles to a Korean father and a German-American mother, who worked as a jazz singer. Shortly after, she went with her mother to live in Japan, before coming back to states and settling down in Chicago, where Kimberly was raised for most of her childhood.
Before starting her own band she sang and played keyboards for Norwegian black metal band Ancient from 1996 to 1997, and during those years was also the touring keyboard player for Swedish symphonic metal band Therion. She also played live keyboards for Dimmu Borgir, having toured with them throughout the world in support of their Enthrone Darkness Triumphant album. She then went on to temporarily play keyboards for Children of Bodom during their 1998 European tour while their own keyboardist was occupied with school. She was in a long term relationship with and eventually married guitarist Alexi Laiho (who plays lead guitar for both Sinergy and Children of Bodom), but the couple separated in 2004. Although no longer together, they still remain close friends. They both share identical tattoos of a coiled snake around their ring fingers and also have each other's initials tattooed on the upper part of their left arms.
Goss started her career in music early, debuting as a singer for the underground band Avernus at the age of fifteen. She went on to write and publish her own underground extreme metal fanzine at the age of sixteen, interviewing widely recognized bands such as Emperor, Darkthrone, Mayhem and Bathory, to name a few. At seventeen, she moved to Norway in order to pursue an offer she received to play in the band Ancient. After recording one album with them, they went on tour with Dark Funeral and Bal-Sagoth. 2 days after that tour ended, she was also invited to play keyboards and sing backing vocals on Therion's world tour in support of their Theli album. With Therion, she toured with bands like Amorphis, Sentenced and My Dying Bride as well as playing major European festivals like Dynamo Open Air. In 1997 she was also asked to join Dimmu Borgir as a session keyboardist where they went on to tour with In Flames, Krisiun and Kreator, to name a few. During the tour with In Flames in August 1997, she met guitarist Jesper Strömblad and together they formed the first incarnation of Sinergy. She moved to Sweden in 1998 to rehearse with the first line-up of the band and proceeded to record their debut album, Beware the Heavens. Shortly after, she relocated once again and moved to Finland, where together with original band member Alexi Laiho, they reformed Sinergy with Finnish musicians. Over the years Sinergy has teamed up to tour with the likes of Nightwish, Angra, Dark Tranquillity, In Flames and Children of Bodom. They've also played some of the biggest metal festivals in the world including Wacken Open Air. Their success in Japan led Kimberly to receive an offer to write a monthly column for over 3 years in Burrn! magazine, the country's most popular music publication.
The fourth Sinergy album, Sins of the Past, began production in 2004, but due to Children of Bodom's busy schedule the album was never completed. Alexi Laiho stated in an interview with Ultimate-Guitar.com in February 2011 that Sinergy is now defunct.
In the summer of 2011, Kimberly began scoring background music for various TV shows that have aired on ABC Family, Syfy and MTV, among others.