When we talk about character development, most of the time we’re focused on the main characters: the protagonists and the villains. And the result I’m seeing over and over is that, while authors are developing these wonderfully complex, complete main characters, the secondary players are falling by the wayside, left as two-dimensional figures used mainly to propel the plot forward—helping the main characters get what they want, or getting in their way, without contributing much to the depth of the story.
But here’s the thing about sidekicks and supporting characters: they’re all the protagonists of their own stories.
Every member of your supporting cast brings a lifetime’s worth of experiences, values, quirks, and perspectives to the table, and the more you can honor that by fully developing every character, the richer your story will become.
Think about the most memorable supporting characters you’ve read. One of my favorite examples is the rest of the Bennet family, in Pride and Prejudice. Though Elizabeth is the main character, most of the rest of the immediate family is developed with as much depth, nuance, and precision as she is. We laugh at Mrs. Bennet’s social foibles and her “poor nerves,” but we also sympathize with her urgent desire to be sure all her daughters are well taken care of once their father passes away. Mr. Bennet’s wry apathy is a brilliant counter to his wife’s anxiety, but his desire to see his daughters (especially Lizzy) grown up, mature, and fulfilled (by more than just money) shines through his quiet nature. And the other sisters are more than props and foils—each has her own set of values, her own strong opinions, and her own distinct personality. (Though I’ll concede Kitty and Lydia might as well be one girl.) Though this story is primarily about Elizabeth and Mr. Darcy, the depth and complexity the supporting characters add to their lives makes for a much richer, more colorful novel overall.
Now, let me be clear: you can’t give every character’s development the same treatment within the novel, itself. If you spent as much time expounding on Mr. Collins’s and Charrlote’s and Kitty’s and Mr. Wikham’s backgrounds, histories, and beliefs as Lizzy’s, your novel would be thousands of pages long. But you can (and should) do the same behind-the-scenes development work on everyone, because the more you know about these secondary characters and the more you can get into their heads, the easier it will be to suss out how they’ll interact with your main characters and the richer, more complicated those relationships will become on the page.