Trusler was born in London in 1976 and began playing the violin at age three. As a child he studied with Sheila Nelson, and he entered the fast track when he won the Frederick Grinke Scholarship to London's Royal Academy of Music. He also studied at the Mozarteum summer academy in Salzburg, winning an outstanding student prize there, and at the Rotterdam Conservatory under Jean-Jacques Kantorow
and then Ruggiero Ricci
, who bestowed high praise upon the youngster. He moved to the Curtis Institute in Philadelphia for studies with Viktor Denchenko, graduating in 1998.
Trusler quickly established a reputation as a rising concerto soloist, performing with a bow once owned by Jascha Heifetz
. He has been particularly effective in concertos of the 20th century, numbering those by Walton
, and Rozsa
among his repertoire. In 1998 he made his recital debut at Wigmore Hall in London, returning there the following year as part of the BBC's influential New Generations series. Trusler was part of a chamber group that recorded Messiaen's Poèmes pour mi for Champs Hill
in 2004. The following year he issued The Pity of War, a collection of violin sonatas shaped by wartime, on Orchid Classics
, and he has recorded mostly for that label, to which he has also signed other artists. His 2010 recording of concertos by Rozsa and Korngold won critical acclaim, and in 2017 he issued an album of Prokofiev's Violin Concertos Nos. 1 and 2. His plans for the late 2010s include Wonderland, an album produced in collaboration with animated filmmakers and marking the 150th anniversary of Alice in Wonderland.
Trusler is the founder of the Lenny Trusler Children's Foundation, which raises money for seriously ill infants. He was also a co-founder of the Malmo International String Festival, and in 2012 he was appointed a director of Delange Artists Management, based in Amsterdam.