'I'm certainly not a minimalist!' But designer Katie Harbison's projects are always as soothing and calming as if she were. She explains how to have serenity when you have stuff, too

Katie Harbison is the founder and creative force behind her eponymous design studio, known for crafting interiors that balance architectural integrity with a warm, contemporary elegance. Drawing on a background that blends classical influences with a love for Californian ease, Katie approaches each project by first honoring the bones of the building, reinstating period details where they’ve been lost, and ensuring the architecture flows seamlessly into the interiors. Her work has been praised for its tactile materiality, thoughtful restraint, and the way each room feels both curated and deeply liveable.

Whether reimagining a historic townhouse in New York or bringing character to a modern build, Katie’s signature is the juxtaposition of vintage treasures with refined, modern lines - plush, deep seating beside smooth marble bars; ornate architraves paired with softly curved sofas. Inspired by Renaissance symmetry and old-world craftsmanship, yet guided by a Californian sensibility of light, space, and natural materials, her rooms invite a sense of calm, beauty, and subtle surprise.

In this conversation, Katie shares the principles that guide her work, from her love of marble and limewash to the importance of negative space, balance, and the little unexpected touches that transform a home from stylish to unforgettable.

How do you begin designing a room? Do you start with a feeling, a color, or perhaps a piece of furniture?

It starts with the architecture. It’s important that there is cohesion right through the home, and you don't want the facade to feel separate from the interiors, so we try to keep those details consistent. I’m currently doing a townhouse in New York and want to reinstate the grandeur that would have been, adding the molding back in, replicating what the skirtings should have been, infusing it with panels and ceiling roses that are as close to the original as possible. But then we look to the Californian aesthetic for the furniture and accessories, brining in linens, soft aspects, juxtaposing vintage and new pieces.

How would you describe the Californian aesthetic that influences you?

It’s about deep comfy seating, woods, soft palettes, a focus on the materiality, rather than being overly fussy or ornate. I wouldn't say I’m a minimalist, as I like to source an abundance of treasures and fill the shelves with them. But then I’ll pair that with something smooth and simple and refined and pared back, like a full marble bar.

How might you design a modern house, that doesn’t give you the same freedom to play with period details?

I’ll find ways to bring other details through the house. Perhaps it’s curved arches, that then get picked up by curved sofas and coffee tables, which will soften the angular corners of a newer build. Ultimately it’s always about finding a balance, that’s the key.

What’s the one element that you think every room needs, no matter the size or style?

Marble for sure - I adore it. I’m using a lot of limewash and plaster on the walls as I love the texture. Our bases are always neutral bone colors, though in areas like powder rooms we do more color drenching, and in main living areas we bring in color through the marble. I particularly like stone with mossy green veining. I look for depth of color, rather than a stone being too deeply or overly veined.

As you say, you’re not a minimalist, but your spaces are still very pared back and each item has space in which to appreciate it. How do you approach that balance?

I would say, when it comes to the larger piece of furniture, I'm always conscious not to put too much in a room. Then when it comes to putting things on shelves, I’m interested in the negative space. It’s not about cramming them wiht as much as you can, but should be about playing with different heights or shapes. I never look for straight or linear lines.

Are there any eras you continually find yourself drawn to for reference or ideas?

Yes, I’m really drawn to the Renaissance period. It’s a lot more ornate. We were in Florence, Italy, last year, and I spent the whole time looing at original architraves, how they integrated them with the marble and the baseboards and the doors. It was so inspiring.

Is that same sense of wonder something you hope to inspire in the people who enter spaces you’ve designed?

I’d like them to be calm and happy. You know when you’re on vacation and you feel particularly comfortable and inspired because the hotel you’re in is curated and well designed? That’s what I look to achieve in a residential setting - it puts people at ease to be surrounded by spaces decorated in that way.

And lastly, what do you think people often overlook when decorating their homes?

Symmetry! This goes back to the Renaissance period, as symmetry is the foundation of design. But I don’t need everything to be totally symmetrical - I’m more interested in particular alignments of things like joinery and panelling. Then it’s good to have one or two things inside the room that are just a bit off. I’m putting a small mirror into a formal drawing room at the moment, on a wall you might expect a larger piece to go. But I feel like there is a lot surrounding it, and so to have something unexpected is where the balance comes in. It’s where you get that little lift.

See more of Katie's work at Katie Harbison Interior Design