Katharina Gast was born on March 12, 1984, in Remscheid, Germany. She began her career in the entertainment industry at the age of fifteen, working as a speaker, actress, and moderator. She gained public recognition as a host for the ARD program Tigerenten Club, a role she held for several years. Beyond her on-camera work, her voice is featured in numerous advertising campaigns, audiobooks, video games, and documentaries, and she has also worked as a station voice for various radio broadcasters.

In the field of voice acting, Gast has lent her voice to a variety of characters in German dubs of anime and other productions. She is known for voicing Aina Ardebit in the 2019 film Promare. Another notable role is Saemonza in the Girls und Panzer franchise, including the television series, the OVA This is the Real Anzio Battle!, and the film Das Finale - Teil 2.

Her other anime voice roles include Asfi Al Andromeda in the Is It Wrong to Try to Pick Up Girls in a Dungeon? series and its OVAs, Manatsu Shiraishi in Kandagawa Jet Girls, Harami Mino in Laidbackers, Hellvy Oberi in Knight's & Magic, Sawa Okita in Tari Tari, Leviathan in Seven Mortal Sins, Ai Makita in Two Car, Nonoka Masaki in Photo Kano, Tinto in La Storia della Arcana Famiglia, and Kanae in Domestic Girlfriend. She also voiced Shizuko Imazaki in Boogiepop and Others and a young Yuzu in The Anonymous Noise.

Gast has worked under the alternative name Katharina Lichtblau. In her dubbing career, she has frequently collaborated with director Daniel Käser, who handled the German adaptation for productions such as Promare, Tari Tari, and La Storia della Arcana Famiglia.