Supporting characters are ones who act to highlight your protagonist’s needs and shortcomings.

In her chapter, CRAFTING EFFECTIVE SUPPORTING CHARACTERS (Creating Characters: The Complete Guide to Populating your Fiction), Hallie Ephron provides several examples of such characters. She points out that Dr. Watson’s function as Sherlock Holmes’ sidekick is to be a sounding board for the brilliant sleuth’s ruminations.

She goes on: 

“Virtually every mystery protagonist has one [supporting character]. Rex Stout’s obese, lazy, brilliant Nero Wolfe has Archie Goodwin—a slim, wisecracking ladies’ man. Carol O’Connell’s icy, statuesque, blonde Detective Kathy Mallory has garrulous, overweight, aging, alcoholic Detective Riker. Robert B. Parker’s literate, poetry-quoting Spenser has black, street-smart, tough-talking Hawk.”

“Supporting characters should come across as ‘real people’ while simultaneously performing a specific set of narrative functions.”

In designing your cast of supporting characters, then, remember to utilise the principle: Opposites attract. To that end, weigh up your protagonist’s traits against those of your supporting characters and offer a contrast between them: Holmes is brilliant and unconventional; Dr Watson is slow and a stickler for decorum. Inspector LeStrade’s dislike of Holme’s whimsical flair provides an incessant critique of Sherlock’s investigative technique. 

You get the idea.

The point is that a level of conflict between your supporting characters and your protagonist, whether these characters are friends or foes, is a requirement if the story is to engage us.

Of course, it is not all strife and conflict with supporting characters. They can often provide comic relief. Shakespeare’s unforgettable Falstaff comes to mind. Still, even here, the main function of such a character is to act as a foil to the protagonist.

Getting the names straight

A last word on naming your supporting cast. Ephron admonishes us to assign names to characters that help us differentiate between them. She states: 

“It’s not easy for readers to keep all your characters straight, so help them out. Don’t give a character two first names like William Thomas, Stanley Raymond, or Susan Frances. Vary the number of syllables in character names—it’s harder to confuse a Jane with a Stephanie than it is to confuse a Bob with a Hank. Pick names that don’t sound alike or start with the same letter. If your protagonist’s sister is Leanna, don’t name her best friend Lillian or Dana.”

There you have it . A snapshot of supporting character functions to get you started.

Exercise: Go through any story you’ve written but not published. How many of your supporting characters act as a foil to your protagonist? Do they provide a humorous or critical commentary on your protagonist and his views? If not, strike these characters from your story, or combine them into one more pithy character.

Summary

The supporting characters’ function is to throw your protagonist into bold relief through praise or criticism, while simultaneously coming across as ‘real people’.