Born in Bonn, Lenny Mockridge studied film music at the University of Brighton in 2011 and has been working as a film composer since 2015. As a theatre musician, he works with directors Anne Lenk, Sarah Kohm, Simon Solberg, Evgeny Titov, Frank Behnke and Kieran Joel, among others. In 2017, he composed the theatre music for Kieran Joel's Johanna D'arc, based on Schiller's Die Jungfrau von Orleans, at the Volksbühne Berlin, and for Miguel de Cervantes' Don Quixote at the Theater im Bauturm in Cologne, which was awarded the Cologne Theatre Prize in 2018.
With Sarah Kohm as director, he worked as a musician for Annie Ernaux's Erinnerung eines Mädchens (Memories of a Girl) for the Schaubühne Berlin in 2022.
In 2023, the Schauspiel Dortmund opened its season with the musical Das Kapital Das Musical, for which Mockridge composed the music and songs. As a music producer, his music is regularly broadcast on channels such as ARD, NDR, WDR, Netflix and Nickelodeon.