According to his own statements, his pseudonym MilleniumKid is derived from his date of birth. MilleniumKid achieved his commercial breakthrough in 2023 with the single Unendlichkeit, which he produced and released together with singer-songwriter JBS. Its success was partly due to a TikTok trend, which saw more than 20,000 short videos featuring the single created by users of the platform in a very short space of time. Together with The Boy The G, a techno remix of the song was also released in 2023. MilleniumKid has been under contract with Warner Music since 2023.
MilleniumKid's music can be categorized as a German-language mixture of new wave, synth pop and indie rock with influences of techno and drum and bass.