Swedish classical trombonist.

He began his Academy of Music studies on tenor trombone for Sven Erik Eriksson in the fall of 1980. On March 10, 1983, he switched to bass trombone for Christer Danielsson, and took his music degree in the spring of 1985.

After completing his diploma studies at the Stockholm Academy of Music in 1987, Lars received the Academy of Music's merit badge together with his colleagues in the Laminaquartetten (trombone quartet) consisting of Åke Lännerholm, Jonas Bylund and Peter Nygren.

He played i.a. Animalen, Glada Änkan and Nine at the Oscar Theater during the study period.

Since autumn 1986, Lars has been employed at the Royal Opera as bass trombonist and double bass trombonist.

He appears in many different contexts, for example guest performances in the Stockholm orchestras and the collaboration with Christian Lindberg in the ensemble Trombone Unit 2000.

The UNIT has performed at the International trombone festival in Texas 2002 and Helsinki 2003. Other members of UNIT are, in addition to Christian Lindberg (world-leading trombonist), Håkan Björkman (solo trombone in the Kgl Hovkapellet) Karl Frisendal (solo trombonist in the Royal Philharmonic Orchestra) Jonas Bylund (trombone professor in Hannover) Sven Erik Eriksson (trombone professor at the Academy of Music in Stockholm) and Jessica Gustavsson (Iceland Symphony Orchestra).

Lars Westergren was bass trombone teacher between 1992-2006 at the Academy of Music in Stockholm.