How the Best TV Shows Build Supporting Characters Audiences Love

Not every character needs to be the protagonist. The best shows understand that supporting characters are the foundation of a great story — and they build them with care.

Think about your favourite TV show. Chances are, you didn't just fall in love with the main character — you fell in love with the ensemble. The quirky best friend. The gruff mentor. The comic relief who breaks the tension at exactly the right moment. Supporting characters make a show's world feel real. They make it worth returning to, week after week.

What separates a forgettable supporting character from one audiences genuinely love? Let's look at how the best shows do it — with examples from some of our favourite cancelled series. According to writing guru John Truby, the key difference between a supporting character and a prop is agency: a great supporting character has their own desires, their own obstacles, and their own transformation arc that runs parallel to the protagonist's. When a show masters this, the audience falls in love not just with the lead but with the entire world the characters inhabit.

Give Them Their Own Arc

The best supporting characters aren't just there to serve the protagonist's story. They have their own desires, conflicts, and growth. In Scorpion, Toby Curtis and Happy Quinn's slow-burn romance was as compelling as any mission. In The OA, BBA (Phyllis Smith) had one of the most moving arcs in the series — a lonely teacher who finds purpose and courage through a story she barely understands. BBA's arc is a masterclass in supporting character writing: she starts as comic relief, evolves into a maternal figure, and ends as a warrior willing to die for a cause she discovered only months ago. The audience doesn't just love BBA — they become her.

According to ScreenRant, the most beloved supporting characters in television history all share this trait: they don't exist to be sidekicks. They exist to be people whose lives intersect with the protagonist's. When a supporting character's arc feels as important as the main plot, the show achieves a depth that no single-protagonist story can reach.

Let Them Be Competent

A supporting character who exists only to make the protagonist look good is boring. The best supporting characters are good at what they do. In Startup, Izzy Morales is a technological genius who drives the plot as much as Nick or Ronald. In Archive 81, Mark is the loyal friend who keeps the real-world investigation going while Dan is trapped in the past. When supporting characters have skills and agency, the whole show is stronger. The audience respects competent characters, and respect is the foundation of lasting emotional investment.

This principle applies even in ensemble shows where every character could technically be called a "main." In Teenage Bounty Hunters, both Sterling and Blair are protagonists — but their father, Anderson, is a supporting character who demonstrates competence in ways that elevate every scene he's in. His ability to pivot from furious parent to reluctant ally makes him one of the show's most memorable characters despite limited screen time.

Let Them Surprise You

The most memorable supporting characters defy expectations. In Teenage Bounty Hunters, Bowser Jenkins could have been a grizzled bounty hunter cliche — but Kadeem Hardison plays him with warmth, humour, and genuine fatherly affection for the twins. He's the heart of the show. In Startup, Wes Chandler (Ron Perlman) should be a simple villain. Instead, he's a man with his own code, his own vulnerabilities, and a daughter he genuinely loves. The best supporting characters refuse to stay in their assigned boxes.

According to TV Guide, the most effective character surprises come from a place of consistency — the character does something unexpected, but the audience can immediately see why they would do it. The surprise is in the action, not the motivation. This is why Wes Chandler can be a ruthless mobster in one scene and a loving father in the next without feeling inconsistent: his code never wavers, even when his methods do.

Give Them Relationships Outside the Protagonist

Supporting characters feel real when they have connections to each other, not just to the lead. In Scorpion, the relationships between Toby, Happy, and Sylvester were as important as their dynamic with Walter. In The OA, the five new "homer" group members — Steve, French, Jesse, Buck, and BBA — formed their own bonds separate from OA herself, making their collective loss at the end of Part II even more devastating. When a supporting character has friends, rivals, and relationships outside the protagonist, they stop being a function and start being a person.

This is a technique that experienced showrunners often call "the dinner table rule": if you can imagine all the characters sitting at a dinner table without the protagonist, and they would still have things to say to each other, then your supporting characters are working.

Let Them Have Flaws

Perfect supporting characters are boring. The best ones have real, visible flaws that affect the story. In Startup, Ronald's ambition repeatedly puts everyone at risk. In Scorpion, Sylvester's anxiety disorders are a genuine obstacle that the team must work around. Flaws make characters feel human — and humans are what audiences connect with. According to writing texts, a character's flaw should be so integral to their personality that removing it would fundamentally change who they are. That's what makes flaws feel real rather than just quirky character traits.

The Greatest Supporting Characters

Looking across all our shows, a few stand out as masterclasses in supporting character writing: BBA (The OA), Bowser Jenkins (Teenage Bounty Hunters), Toby and Happy (Scorpion), Wes Chandler (Startup), and Cabe Gallo (Scorpion). Each one could carry their own show. Each one has an arc that matters independent of the protagonist's journey. The fact that they exist to make another character's story better is a gift to the audience. When a show like Mindhunter builds characters like Bill Tench or Wendy Carr, it's doing the same thing — creating a world so rich that the audience wants to live in it, even after the final episode fades to black.

Great supporting characters are one reason we love TV. And when a show is cancelled, losing those characters — their arcs unfinished, their futures unknown — is part of the pain. Browse our fan-written endings and see how the supporting characters we love get the closure they deserve.