The Many Hats of Musical Theatre: Understanding Common Casting Tracks

So you’ve just auditioned for your local community theatre’s production of Les Misérables and gone through the whole callback session, auditioning for the lead roles of Eponine and Cosette. A day goes by, and you finally receive an offer via email for the role of… On-stage Swing (u/s Eponine & Cosette)??? What does that even mean???

If you’ve ever looked at a musical theatre cast list and wondered what the difference is between a swing and an understudy, or how a principal differs from a featured ensemble member, you’re not alone. Different musical theatre productions use different jargon to describe different roles, and each and every role type serves a distinct artistic and logistical purpose. Knowing how these tracks function can help you understand what you should expect when you audition for shows and what skill sets are required for each track.

Principal Roles

Principals are the primary storytellers of the show. These characters carry the main narrative arcs, major musical numbers, and most of the dialogue.

Think of roles like Elphaba in Wicked, Alexander Hamilton in Hamilton, or Valjean in Les Miserables. Principal roles typically come with the most rehearsal time and responsibility because the dramatic spine of the production rests on them.

What it requires:

• Strong acting and vocal storytelling
• Stamina (they’re often onstage a lot)

Supporting Roles

Supporting roles are substantial characters who help drive the story but aren’t the central focus. They often have memorable songs or scenes and can be scene-stealers. Examples include characters like Olaf in Frozen or Boq/Nessa in Wicked.

Some actors who play supporting characters may double as ensemble members in scenes where their supporting characters do not appear.

Ensemble (The Backbone of the Show)

The ensemble is the engine of a musical. They create the world—townspeople, party guests, dancers, workers—and often sing complex harmonies and execute demanding choreography.

In shows like Les Misérables, the ensemble doesn’t just fill space; they embody the social fabric of the story.

What it requires:

• Versatility (multiple tracks and quick changes)
• Strong dance and blend skills
• Consistency and teamwork

Featured Ensemble

A featured ensemble member is part of the ensemble but has a brief solo, line, or specialty moment—maybe a dance break or short vocal feature. It’s a bridge between ensemble and supporting roles and often a stepping stone for emerging performers.

Understudies

An understudy (or a cover) is cast to learn and perform one or more principal or supporting roles when the regular performer is out. They usually perform in the ensemble or a smaller role while covering.

Understudying demands extraordinary preparedness: you must be performance-ready at any moment, sometimes with minimal notice. In a professional setting, an understudy may be called minutes before or even during a show to go on for the role they are covering.

What it requires:

• Fast learning
• Professional calm under pressure

Swings (The Ultimate Utility Players)

Swings usually cover multiple ensemble tracks—and sometimes principal tracks—rather than one specific role. They may perform a different combination of parts each night depending on absences.

While most swings are usually off-stage (they stand-by backstage), some swings are on-stage, meaning they usually play an ensemble member in a show where there aren't a set number of ensemble members. When a principal calls out, an ensemble member may go on for the principal role, and the on-stage swing may go on for the ensemble track that is more important and missing.

In rare cases where multiple principals or ensemble members are out, swings sometimes perform a split track. In a split track, swings may be asked to perform one ensemble track in act 1 of the show and another ensemble track in act 2 of the show. Usually this is done to ensure important choreography and technical aspects of a show isn't cut due to the lack of actors on stage.

Because they must master choreography, staging, and costumes for several positions, swings are often considered some of the most technically skilled performers in a company.

Why swings are invaluable: A production literally can’t run without them when multiple cast members are out.

What it requires: Everything that is required above, combined.

Dance Captains, Fight Captains, and Other Special Tracks

Some performers take on additional responsibilities such as dance captain, maintaining choreography and leading brush-up rehearsals. Depending on whether a show has a fight scene, a fight captain may be necessary to maintain the safety and choreography of a fight sequence that happens on stage. Others may be standbys or alternates (similar to understudies but not in the ensemble), depending on the production scale.

Why Understanding These Tracks Matters

For actors, knowing these categories helps you:

• Target auditions more strategically
• Appreciate career progression paths
• Recognize that every track requires distinct skills

For audiences, it reveals just how collaborative musical theatre really is. A seamless performance isn’t just about the stars—it’s the result of a finely tuned system of roles working together.

Now let’s try to understand your Les Misérables offer…

Your offer for the community production of Les Misérables states “On-stage Swing (u/s Eponine & Cosette).” While most swings are off-stage, because it says "on-stage swing" you are probably expected to perform as an ensemble member when the show happens. You are also expected to be covering a few different ensemble tracks, different than what you usually perform, in case any ensemble members fall sick and cannot perform the show. Finally, “u/s” is short for understudy, meaning you will understudy for the principal roles of Eponine and Cosette in case the principal actors fall sick and cannot perform the show.

Congratulations! You have booked one of the most demanding roles you will ever get in any production of Les Misérables. The sheer amount of technical skill and emotional readiness you need for this specific track is immense, and the director probably gave you this track because they truly believe in your ability to handle it. Be proud!!!

Every role is important!

No role type is “better” than another—they’re simply different ways of contributing to the storytelling. Whether you’re center stage as a principal or tracking five ensemble parts as a swing, you’re part of the same mission: bringing a world to life however many shows a week.