Carlos Dell’Acqua’s decision to build a home on a steep site in Malibu began with a chance encounter. In late 2000, he was hiking and paused at a vacant lot to catch his breath and take in the spectacular view. Suddenly, a neighbor appeared. “Nice, isn’t it?” she said. “But it’s not for sale!”

Dell’Acqua, an Argentine-born art collector and architect-turned-travel-entrepreneur, wasn’t looking to move from his Santa Monica apartment. But the neighbor, a realtor, insisted on exchanging business cards. Dell’Acqua forgot about the conversation, but several months later, while in China, he received a message from her that the property was available.

The 0.45-acre parcel (plus a small, nonadjacent credit lot) was bargain priced. “I thought: What could go wrong?” he recalls. “I made my offer from China, but all the way home, I kept thinking: Oh, what did I do?” Wisely, he had negotiated a contingency that the lot be buildable. And so began his 14-year odyssey—stymied at times by coastal regulations—from purchase to completion.

Although trained as an architect, Dell’Acqua chose not to design his own house. After working for Richard Meier & Partners for eight years on the Getty Center, he “went through postpartum depression when it finished” in 1997, he says of the complex project he helped bring onto computers, well before that was the industry standard. He then took a leave of absence, largely in Cuba, and envisioned a travel business, now called Art Quest International, which curates trips, typically for museum directors and trustees. “I was just following my passions,” he says, “art, architecture, and travel.”

For his home, he turned to local designer Thomas Egidi, of Tuna Studio Architecture, whose minimalist work, with its exposed concrete and metal details, Dell’Acqua had admired. Together, they settled on a scheme for a 1,887-square-foot house with a 77-foot-long front wall and a steel-framed entry bridge spanning the hill’s precipitous drop. “The brief was to do something very simple and close to the street,” says Egidi.

From the road, the house looks like a freestanding plane. But once across the bridge and through a central opening in the wall, you begin to see the volumes hidden behind it. “It’s a blind wall,” Dell’Acqua says. “But then you enter, and wow! That’s one of my favorite moments.” Suddenly, views open to the living room (one floor below), out to a terrace with a small swimming pool, and beyond to a panorama of mountains cascading into the ocean.

The wall—which changes imperceptibly, but economically, from cast concrete at the bottom to troweled stucco above—also serves key functional roles. It retains the slope and conceals electricity-generating photovoltaics on the roof. For additional privacy, a “smart” glass front door instantly switches from transparent to opaque with a tap of Dell’Acqua’s phone.

Just over the threshold, two rectangular volumes flank the passageway, where a stair winds down to the lower level. One wing contains a home office with the living-dining-kitchen area below; the other houses the garage over the guest and master bedrooms. Throughout the structure, exterior and interior spaces flow together and share a material palette. Evoking a beach boardwalk, ipe planking leads from the outdoor entry bridge into every room and out onto the terrace. Dell’Acqua selected ipe to “soften” the palette of concrete, glass, and steel, but also for its durability and fire resistance. In another indoor-outdoor feature, the front wall has the same raw, unpainted quality on its exterior and interior surfaces. And in back, sliding glass panels open the living room and master bedroom to the terrace, with a poolside shower exposed to the elements yet concealed from outside view.

On his global jaunts, Dell’Acqua handpicked light fixtures from Finland, lumber from Holland, and textiles from Argentina. Also, Egidi recalls, “Carlos would send me pictures of things he encountered—like a backsplash that I then reinterpreted.”

“The upside to spending so many years imagining my house is that I had time to think about every detail,” says Dell’Acqua, who shares the home with his partner and their chocolate Lab. The furnishings are primarily white, gray, and black, with blue accents, echoing the water, a theme in Dell’Acqua’s contemporary art collection. Now when Dell’Acqua is home, he says, “I feel like I’m on vacation. I never get tired of it.” The changing light and tides constantly bring unexpected moments, he adds, “like when I’m sitting in the living room, and the rim of the glass rails exactly meets the horizon line. How could you possibly plan that?”