[4] Penkin began his career with composition credits in the 2011 short films Play Lunch and The Adventures of Chipman and Biscuit Boy.
[8] Penkin's relationship with Kinema Citrus continued through to 2017 for the soundtrack of Made in Abyss,[8] winning the 2017 Crunchyroll Anime Award for Best Score with it.
[9] Penkin composed the music for Kinema Citrus' anime adaptation of The Rising of the Shield Hero and NetEase's VR game Nostos in 2019.
[11] Penkin was working with artist Takashi Murakami on the sequel to the movie Jellyfish Eyes, but the project was cancelled due to the COVID-19 pandemic.
[12] In 2021, Penkin composed the score for "The Village Bride" episode in the Disney+ animated anthology series Star Wars: Visions.