Like many New Yorkers with grown children, Gail Shields-Miller and her husband, Andrew Miller, decided they needed to downsize their living space. After four years of fruitless searching, with a number of deals going belly-up and co-op boards proving difficult, the couple took up full-time residence in their Fire Island home, exiting a three-bedroom Upper East Side apartment.

The commute was exhausting, and they often ended up staying in hotels in the city. Finally, it dawned on them that they could buy a pied-à-terre in one of the hotels.

The Millers purchased an 850-square-foot one-bedroom apartment in the Lombardy, a 1920s-era hotel in East Midtown, where 40 of 165 rooms are available to buy. There are studios, one- and two- bedroom apartments, duplexes, and three-floor penthouses. The couple now spends most weekdays in the apartment, opting for Fire Island on the weekends.

While she now describes the apartment as “so the right place for us,” Mrs. Shields-Miller wasn’t always so confident. When she first saw the apartment, she worried it was too small and disliked its long, narrow entranceway. Also, the previous owner hadn’t touched it since the 1960s, and it felt outdated.

Luckily, Mrs. Shields-Miller, who is an interior designer and the owner of Shields & Company Interiors, knows a thing or two about making the most out of small spaces. She was able to achieve a spacious and comfortable feel while expressing her modern, eclectic style. She said she’s so pleased with the final result that she often uses the apartment as a showroom for potential clients.

For the problem entranceway, Mrs. Shields-Miller employed various designer tricks: She added large walnut moldings (something she recommends to clients in small spaces because they trick the eye), installed mocha-colored Spanish limestone tiles for the floors (they were left over from the Fire Island house), and put up antique silver-leaf wallpaper embossed with figurative Asian symbols.

“People think that if you have a small space, you have to use small pieces and stick to basic white. But bolder moves make a place more interesting. You shouldn’t be afraid of larger scale items in small spaces,” she said. “They actually make it feel bigger.”

Right off the hallway is a tiny kitchenette, which Mrs. Shields-Miller opened up by removing its door and all but the tops of its two exterior walls. Checkered tiles of white, black, and tan now line the interior walls. While Mrs. Shields-Miller admits she’s never used the stove top, built-in floating shelves and a fair amount of cabinet space assure that, if she ever wants to cook, she can.

The living room is bright and airy, and conveys Mrs. Shields-Miller’s taste with sculptures and art she has collected during her travels, bought at antique stores, and taken from her childhood home on Long Island. Some of it is very modern, some antique.

The furniture is upholstered with a variety of different fabrics, including floral, spotted, and striped, each of which manages to complement the others. Much of the furniture she’s designed herself. “There’s very little in this room that was just bought off the floor,” she said, pointing to a glass-top table with a base made of steer horns she designed.

On opposite walls hang a print by Salvador Dalí and two by Andy Warhol. Another wall features dark-wood built-in floating shelves, on which Mrs. Shields-Miller displays books, a stereo, vases, and various other pieces.

When the couple first bought the apartment a lack of overhead lighting made it very dark, so Mrs. Shields-Miller had coffers built on the ceilings. The floors in the living room and bedroom are carpeted to ensure quiet for downstairs neighbors, a requirement for hotel living.

Off the living room is a small space that serves as an office and dressing room, with built-in closets. Originally part of the bedroom, Mrs. Shields-Miller divided it by adding modern French doors.

Even the bathroom, which is now off the office/dressing room, has Mrs. Shields-Miller’s designer touch. She’s employed the using-big-objects-in-small-spaces technique by placing big pieces of fossilized French limestone on the floor and walls. The sink and countertops are made of marble, and the floor and ceiling of the shower are covered in glass tiles. “I’m a tile freak,” she said.

The bedroom walls are lined with silver wallpaper with a pattern of oversize chrysanthemums. There is a king-size upholstered bed, which Mrs. Shields-Miller designed, with a headboard covered in a chenille-style fabric and a base covered in Ultrasuede. There is also a large, Art Deco-style dark-wood dresser she found in Los Angeles — a piece she says inspired her to go for the look of Hollywood glamour.

Many pieces of furniture (including a desk, night table, and dining room table) came from the Millers’ old apartment. “It was wonderful to see how these pieces reinvented themselves in a new space,” Mrs. Shields-Miller said.

In addition to their interior space, the Millers said they enjoy their new neighborhood. For Mrs. Shields-Miller, it’s particularly convenient to be near the interior design district. “It’s such a grown-up neighborhood,” she said. “We can walk to the theater, it’s easy to get uptown and downtown. The city’s in our hands.”

There are also perks that come with living in a working hotel: concierge service, the opportunity to meet lots of different people, the security of knowing that someone’s keeping an eye on your place even while you’re gone, and, perhaps the best part of all: a cleaning service. Cleaners come every day to do general work (which includes washing dishes, cleaning the bathroom, making the bed, and changing the towels); once a month they’ll do a thorough cleaning, which includes the windows.

Another perk is the relaxed co-op board that encourages owners to make changes to the apartment. “At first we weren’t going to do much to it, but, honestly, it would have felt like buying a new dress and wearing old shoes,” Mrs. Shields-Miller said.