The living room of the wooden bungalow high on an East Honolulu hillside pulsed with the morning light shining through its many windows.

Breeze Giannasio, standing barefoot on the dark wood floor in a long, flowing dress, her long, dark hair swept up in a topknot, smiled and welcomed visitors through French doors onto a raised front porch with a panoramic view of a freshly green Diamond Head Crater and the sparkling sea.

Born and raised on Oahu, Giannasio, 41, a Los Angeles-based interior decorator and former litigator at Latham & Watkins, a top law firm in Washington, D.C., is remodeling the 1931 house for Jovanna and Dylan Fern, her sister and brother-in-law, who bought it and moved in with their two young daughters a little over a year ago.

One of the first things she did, after consulting with the couple on a master plan, was to rebuild the foundation and extend the porch six feet out from the house, adding a new railing and roof overhang and transforming the space into more of a lanai, with room for a small table and chairs.

To accommodate the family’s lifestyle and budget, Giannasio has planned for the renovations to be done in stages over three to five years. The phased project also will provide more excuses for her to return home and visit her close-knit family. Her dream is to establish a business in Hawaii, and recently actress Sarah Wayne Callies (“The Walking Dead,” “The Long Road Home”), a Punahou classmate and close friend, helped provide a pathway toward that goal.

Callies wanted tiles with a Hawaiian quilt motif for her home in L.A., Giannasio said. Unable to find them, the friends decided to partner on producing the tiles themselves. That grew into plans for a line of Hawaii-inspired textiles, tiles and wallpaper that Giannasio has begun developing while working on residential projects on the mainland and hotel design in Asia, where she has worked with Michael Bedner, formerly of Hirsch Bedner Associates, which refurbished the interior of the Kahala Mandarin (now the Kahala Hotel & Resort) in 1996.

IN 2017, two celebrity home projects in L.A. raised Giannasio’s profile. In the spring, she redid the condo of actress Mila Kunis’ parents for “My Houzz,” an online video series about celebrities who surprise family members with the gift of a home renovation.

Last fall, she appeared in five episodes of a special spinoff of “The Property Brothers,” the popular HGTV show starring twins Jonathan and Drew Scott. Giannasio was tasked with a fast-paced, 12-week conversion of a Larchmont, L.A., fixer-upper into a baronial but comfy honeymoon home for Drew Scott and Linda Phan in time for a pre-wedding, housewarming party.

The 1920s house had been occupied by the same woman for 75 years and was “really trapped in time,” Giannasio said. “It’s almost a miracle to find houses that haven’t suffered through bad renovations.”

She respected the character of the home, taking care that where they did modernize, it didn’t show. Structural additions included windows and interior molding made to look “as if it was always there,” as well as a roof deck and 20-foot extension into the backyard.

It was in the interior decoration that Giannasio gave herself freedom to reflect the couple’s tastes. “Linda likes color and pattern, Drew is a little more minimal, so I was trying to harmonize their disparate desires.” In the end, “The design aesthetic was actually inspired more by ‘L.A. art deco meets Parisian bistro vibe.’”

The couple loved it.

The finale of “Property Brothers at Home: Drew’s Honeymoon House” presented the new roof deck and back lanai, both with plenty of space for entertaining. One of Giannasio’s key design principles is having interior spaces that flow effortlessly into the outdoors, which she learned through growing up in Hawaii homes.

“Thinking back to my childhood and napping on a lanai on a punee, Hawaiian style definitely informs everything I do, particularly a celebration of natural materials and an effortlessness to living,” she said.

FIVE YEARS ago, Giannasio, who as a child growing up in Lanikai moved furniture around the house and drew arboreal “Star Wars” Ewok villages that she hoped to build someday, left the practice of law to pursue her master’s degree in interior design. After studying at the Corcoran College of Art & Design in Washington, D.C., and the Royal College of Art and Design in Copenhagen, Denmark, she trained with an architectural firm for two years.

As with the “Property Brothers” project, her plan for her sister’s three-bedroom, two-bath bungalow — one of several modest but gracious homes the Matson shipping company developed in the 1930s around Wilhelmina Rise in Kaimuki — preserves its period architecture while providing more eclectic interior design.

A King Charles spaniel darted underfoot as Giannasio and Jovanna Fern, 37, also wearing a long dress, gave a tour of the living room. The designer pointed to a tall, curvaceous armchair she’d upholstered in teal blue.

“That’s an Egg chair by Arne Jacobsen,” she said with pride, referring to the Danish architect and designer known for his simple, elegant chair designs. It was paired with another small modernist armchair in rattan and steel that had been rescued from the side of the road just down the block.

Her scheme blended mid-20th-century modern style, including a large, black-and-white abstract painting that Fern found in a Kaimuki consignment shop, with vintage and Hawaiian elements, such as a palm-tree-print pillow and a rusty metal sign that spelled “Aloha” that Giannasio had found at the Rose Bowl flea market in Pasadena, Calif.

“The long-term plan is to add a mother-in-law suite downstairs,” Fern said, “and we added French doors to enter that space, although it’s unfinished.” The couple also plans to add a master bedroom suite and bathroom in the back of the house.

Meanwhile, they’re awaiting the delivery of Roman shades for the windows, and next year they’re refinishing the original wooden floors.

The project is a win-win for the family, Giannasio and Fern said: The longer it takes to finish the house, the more time they get to spend together.