He has also worked with the supergroups Star One, Allen-Lande, Adrenaline Mob, Level 10, and as one of fourteen vocalists in the progressive symphonic metal band Trans-Siberian Orchestra.

Before his music career began, Allen was a jouster at a Medieval Times Dinner Theater at the Lyndhurst, New Jersey location from 1990 to 2002.

In the summer of 2005 he went on tour with Symphony X on Dave Mustaine's Gigantour alongside such bands as Dream Theater, Megadeth, and Nevermore.

The same year, he also made part of a duo melodic rock project with singer Jørn Lande (ex-Masterplan) called Allen/Lande, which has four albums, all released by Frontiers Records.

In 2014, a new project was announced, featuring Russell Allen with bassist Mat Sinner and other members of the German band Primal Fear, called Level 10, with an album release slated for January 2015.

Russell was one of the few singers with whom I didn't need to be present during recording, but when on the phone he let me hear the parts he had sung, my eyes filled with tears.