The 'Sidekick Color' Rule Designers Use to Keep Rooms From Feeling Flat

Well-designed rooms don't use color in isolation; the whole palette works together to bring color harmony through a mix of hero colors, background colors, and sidekick colors. But what exactly are these 'sidekick' colors? Sidekick colors are present in all of the most interesting rooms, working alongside the hero color to support it, without taking over. These secondary colors can be quiet, but they tie the whole palette together and stop room color ideas from feeling disjointed.

'I think it's important to design with a color palette rather than relying on one color to carry a room,' says designer Lacey Michalek. 'Even when we have a dominant color, we're always looking for coordinating shades that complement it and bring something different to the space. Those supporting colors create contrast, add depth, and keep a room from feeling too one-note. Without them, even a beautifully designed space can start to feel a little flat.'

And so, if you're intrigued by this color term and want to know how to use it to add more design flair to your own home, designers share all you need to know here, from how to choose sidekick colors to real-life examples.

What Are Sidekick Colors?

While you may not have heard the term 'sidekick' colors before, they're present in most well-designed rooms. Essentially, sidekick colors are the supporting colors within a room, working to enhance or lift the hero color (the color that has the strongest visual impact). Sidekick colors aren't to be confused with background colors that form the foundation of the room and are often neutral tones.

Think of sidekick colors as the ones that work to support the room's color palette, rather than being the focal point.

The key thing to keep in mind when thinking about sidekick colors is that they can be all sorts of colors, from soft shades to much bolder ones. What makes a sidekick color a sidekick color depends on the wider palette of a room, and how the colors relate to each other.

'We use sidekick colors in our projects because the right layering creates depth and balance,' says designer Linda Eyles. 'Although they play a supporting role, they are just as important as the hero color in a room because they make the star look rich and vibrant. A space with no sidekick appears dull and flat.'

Why Sidekick Colors Matter

Designers will tell you that creating a color hierarchy, where each color has a specific role in the room, is what makes rooms feel intentional and grounded rather than random. Within color hierarchies, sidekick colors are essential in bridging the gap between the hero color and the foundation, bringing a sense of harmony and calm.

'Sidekick colors are so important because they add depth and interest to a space without competing with the main color,' explains Amy Peltier, owner and creative director at Peltier Interiors. 'Sometimes you barely even notice them because they're used so subtly or sparingly, but that's exactly the point.'

'They help the dominant color shine while giving the room a more layered, interesting feel,' she adds. 'Without those supporting colors, a room can easily feel a little one-note or flat, even if the main color is beautiful on its own.'

When sidekick colors add contrast to the hero color, rooms tend to feel more elevated. 'I think the magic of a room often comes from the things you don't necessarily expect to see together,' says Ansley Majit, creative director at Lark + Palm Interiors. 'A sidekick color gives a space another dimension, a little tension, and often a bit of personality. Without it, a room can feel a little too coordinated, a little too predictable.'

'I love when there's a color that feels slightly unexpected but somehow makes everything else in the room better,' says Ansley. 'It's that little twist that takes a room from pretty to interesting.'

Sidekick colors serve another purpose, too: they can be used to soften what would otherwise be a high-contrast palette, making bold colors more digestible. You'll also find that they are a great way to incorporate the latest color trends that you perhaps wouldn't want to use in a large proportion.

How to Choose a Sidekick Color

While the idea of adding a sidekick color to a scheme makes a lot of sense, how do you actually go about choosing one? There are a few different ways you can go with this, but essentially, it's about considering what color will work well alongside your hero shade.

'If we're designing something calm and subtle, I'll gravitate toward softer, more muted shades that complement the dominant color without competing with it,' explains designer Lacey Michalek. 'But if we're going for a moodier, more dramatic look, I love incorporating richer, more saturated versions of the dominant color to create a stronger contrast. A sidekick color doesn't necessarily have to be quiet. It just needs to work with the dominant color in the palette.'

Alternatively, you could choose your sidekick color by pulling existing colors found more subtly in the room. 'Usually, there's a pattern or rug in the room that helps establish the color palette,' advises Amy Peltier. 'We'll pull colors from that inspiration piece and decide which one will take center stage and which ones will play a supporting role. The key is making sure those secondary colors complement the overall design without shifting the entire feel of the room.'

'Other times, we're simply working with a palette of two or three colors that look beautiful together,' says Amy. 'But I always think it's important to have one star of the show. The supporting colors might be softer in intensity, lighter in shade, or just used more sparingly. Otherwise, you end up with too many cooks in the kitchen, and suddenly every color is fighting for attention.'

The color wheel should be your friend when choosing sidekick colors – giving you a reference point of the harmony between different colors. 'We often choose a color that is complementary to the main shade we are using in the room,' says Linda. 'In other words, a hue that is on the opposing side of the color wheel. These supporting sidekick colors pair well together because they each appear richer when side by side.'

'It also works to pair what I think of as 'sister' colors – shades that sit beside one another on the color wheel – blue with green, for example, or pink and red,' Linda adds. 'These combinations tend to be a little more playful and vibrant.'

That said, sidekick colors can be less formulaic and unexpected. 'Sometimes it's a color that feels completely unrelated at first glance,' says Ansley. 'I love playing with combinations that aren't immediately obvious. The goal isn’t really to match, but to create something that feels layered, complementary, and a little less expected.'

How to Decorate With Sidekick Colors

If you're looking for some real-life examples of sidekick colors, read on to gain inspiration from a range of designer projects, from kitchens to living rooms.

Choose Complementary Colors

Complementary colors, those that sit opposite each other on the color wheel, bring harmony to rooms, despite being contrasting. This approach is shown in this kitchen, where muted green works are the hero color, along with soft pink as the sidekick.

'This kitchen has a very neutral foundation, so we introduced soft green on the island and a warm, rusty pink on the upholstered stools to bring in some color and contrast,' explains Lacey. 'Neither shade is overpowering, but together they add contrast and personality to the space.'

Go Tonal With Analogous Shades

Another way to use the color wheel when choosing a room's color palette is to look for analogous colors – those that sit beside each other. Rather than bringing contrast, analogous color schemes are tonal and tend to feel calmer.

'We chose to color-drench the dining room in a soft green, giving the space an enveloping feel,' explains Lacey. 'For the sidekick color, we incorporated blue through the upholstered dining chairs and drapery to create a gentle contrast. Because both colors have a similar softness, they complement each other beautifully without making the room feel busy. The blue adds another layer of interest while maintaining that calm, inviting atmosphere.'

Mix Warm and Cool Tones

Mixing warm and cool tones adds contrast to rooms and can be a great way to add more depth to palettes. In this white living room, the dark blue works as the hero color, while the coral cushions are the sidekick color that brings warmth to the otherwise cool-toned palette.

'Blue is definitely the dominant color in this living room, but we wanted the space to feel feminine, fresh, and lighthearted, so we introduced a beautiful salmon color through the pillows,' explains Amy. 'Blue and orange are complementary colors on the color wheel, so this softer, salmon interpretation works beautifully against the blue.'

'The combination feels colorful and layered without losing that strong blue identity,' says Amy.

Layer Earthy Colors

Although hero and sidekick colors can be contrasting, choosing shades with a shared earthiness helps bring cohesiveness to the palette. In this nursery room, soft green walls are teamed with mustard yellow, which brings interest and design flair to the space, without feeling totally random or disjointed.

'Mustard as a sidekick color is great when paired with more classic shades like blues and greens,' says designer Shelbie Cox of Shelbie Cox Studio. 'It adds a playful yet elevated feel to the spaces that are decorated with it.'

Let Pattern Inform Your Color Scheme

Pulling a sidekick color from an existing pattern in a room is another designer-approved way to approach sidekick colors, helping to add cohesiveness. 'The wallpaper really sets the tone with its warm, earthy palette, and then we introduced this beautiful blue on the ceiling,' explains Ansley.

'There is a small touch of a version of this blue in the wallpaper, but we pushed the saturation with the color to create this lovely contrast between the two,' she adds. 'The blue brings a freshness and lightness to the room that keeps the warmer tones from feeling too enveloping. It's a little unexpected, but it also feels completely natural. Without it, the room would be lovely, but I think the blue is what gives it that extra bit of personality.'

If in Doubt, Go for Green

If you're not sure which color to add to lift your palette, designers often recommend decorating with green. It's one of those colors that works with pretty much every other color, since it feels natural.

In this bedroom, green adds interest and stops the blue and white combination from feeling flat, but it doesn't make too much of a statement. 'Even with the green incorporated into the design, you still look at this room and immediately think of it as a blue room because the majority of the palette is made up of varying shades of blue,' says Amy.

'Green is actually one of my favorite sidekick colors because it can almost disappear into a space,' she adds. 'Think about greenery in a vase. Technically, you're introducing another color, but it feels so natural that we almost treat it as a neutral. That's what makes green such a wonderful supporting color. It adds freshness, depth, and interest without taking attention away from the main palette.'

Sidekick colors are important in all sorts of color palettes, whether they're bold and daring or soft and muted. Either way, they work quietly to bring unity to the space, from balancing bolder tones to adding much-needed contrast and depth.

By thinking of each of your color choices as part of the wider palette, rather than in isolation, you'll find that your rooms feel far more considered and intentional. Don't forget that referencing the color wheel is a helpful starting point – choosing either complementary or analogous colors always works well.

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