Shearer is most famous for his work as lead trombonist and music director for the Stan Kenton Orchestra, since taking over the lead chair from Jim Trimble in the late 1960s until Kenton's death in 1979. He led the band during Kenton's illnesses, and produced several of the band's last recordings. From 1979 to 1982 Shearer was the director of Wayne State University's (Detroit) Jazz Bands.
Shearer's lead trombone style is characterized in up-tempo tunes by aggressive, wide slide vibrato at the end of held notes, often climaxed with a "tear-off", a technique frequently utilized by lead trumpet players. This technique rarely carries over into the Kenton "ensemble ballads", however.
In soft ensemble passages (such as the famous Dee Barton arrangement of "Here's That Rainy Day"), Shearer plays extremely softly, achieving a true orchestral pianissimo; this technique allows the later ensemble climax to seem even more powerful. Shearer also championed what is referred to as the "breath attack", whereby repeated notes (usually in a ballad) are not tongued, but are given an extra "push" of air.