Colorful flowers in a botanical garden or green and blue underwater sea creatures swimming along a coral reef – the mind conjures such images when viewing the alluringly aerial art of Jason Michael Hackenwerth – made entirely of balloons.

Sculptors tend to hew stone, hammer metal, or mold clay. Mr. Hackenwerth blows, twists, and shapes inflated plastic into configurations as magical and ephemeral as sand castles at the seashore. Mr. Hackenwerth draws inspiration from the plant and animal kingdoms’ “combination of spirituality and sexuality.” Of these plastic shapes, he said: “I’m filling them. The air inside is slipping out. It’s a great metaphor for our own lives.” The works sag with gravity over time, shrinking as they age, “a perfect combination of sadness and joy.” Mr. Hackenwerth’s work celebrates exuberance while transcending the carnivalesque.

Last month his alma mater, the Savannah College of Art and Design, commissioned him to make a roomful of sculpture for a fashion show reception with attendees such as Andre Leon Talley and Tom Ford. He transformed the room with a piece called “Spawn,” a battle of the sexes. Orange, magenta, and yellow males called “Brine,” with jagged teeth, bristly spikes, and 12-foot whiskers mixed with lime-green and flesh-colored females called “Berthas.” “They all look like they came from the bottom of the ocean of another planet,” he said. Air from overhead vent pipes made the balloons undulate, especially the small ones trailing under the female creatures.

Some of Mr. Hackenwerth’s balloon designs are so large he literally has to wrestle pieces into place. The powder from balloons can make his hands brittle and dry, and he now wears goggles to protect his eyes and earplugs when he cuts up a sculpture. He buys balloons by the caseload: 5,000 at a time.

This month he returned from the Venice Biennale where he traveled on a “roving artist grant,” producing a series of public sculptures called “Foraging the Nectar.” From dock posts up and down the Grand Canal, he hung balloon flowers that waved in the wind. On the final day of the opening week, he sculpted “Megamite,” an oversized balloon outfit armed with playful balloon missiles. (Imagine a multicolored, missile-toting Michelin Man.) At one point, he engaged with two stationary robots made of motorcycle parts.

At the end of the day, Mr. Hackenwerth drew a crowd in Piazza San Marco as he destroyed the outfit with a box cutter. “It sounded like fireworks or machine gun fire” as he cut up his creation. “All that’s left was a little pile of color like a grease spot.”

Closer to home, the artist can be seen many weekends perched atop a large round platform at FAO Schwarz, creating sculpture embodying the “spontaneous expression of that day. “The most common questions young and old ask are, “What is that?” or “What are you doing?” At the end of the day, he starts to break down the sculpture and give the balloon pieces to kids gathered. He describes the scene as “a feeding frenzy.”

In his Long Island City studio, Mr. Hackenwerth has created brick-shaped fossils showing the former shape of balloon sculptures. He is also vanquishing the ephemeral nature of balloons by photographing the sculptures so closely that they don’t seem to be balloons at all.

Mr. Hackenwerth has been experimenting with how light passes though balloons and creates shadows. Just how did he first become interested in this elastic medium? His story starts an hour southwest of St. Louis in the small town of Pacific, Mo., where his mother, a single parent, worked in a local factory. Balloon sculpting was “something my mother had done on weekends,” he said. “She would dress up as a clown and make balloons into poodles and swords for extra money at Union Station [a former train station turned into a retail mall].” He recalled being embarrassed as a 14-year-old hanging around with his friends and seeing his mother leave the house dressed as a clown.

He went on to study fine art and painting at Webster University, working nights at Kinko’s. Eventually he apologized to his mother and asked her to teach him to shape balloons. From the tip jar, he earned in three hours the equivalent to almost half a week at Kinko’s. He quit his job at the copying company. Later he pursued painting in Kansas City, Mo., while his partner, Anna Ortt, finished her degree in photography and art history at the Kansas City Art Institute. (She is now assistant director for Littlejohn Contemporary, as well as an independent curator and dealer in New York.)

The two arrived in Savannah, Ga., on September 11, 2001. He pursued his M.F.A. in painting at Savannah College of Art and Design, earning extra money by going down to River Street in his flip-flops and “Jimmy Buffett” look, making balloons for children or balloon hats for late-night revelers. In his senior year, he was awarded a fellowship to come to New York and work out of a studio on 39th Street in Hell’s Kitchen.

When he moved here permanently in 2003, he would enter the New York subway with spray adhesive or double-stick tape to make colorful balloon sculptures and photograph them. “The way graffiti artists tag, I was doing that with balloons.” He was invited overseas to participate in the “-scope London” art fair in 2004. He set up balloons in the shape of a thousand small red, orange, and yellow flames on pillars of the hotel it was held in, so that it seemed balloon fire had engulfed the lobby.

The work was based on the Great Fire of London as well as the color-coded “terror alert” warnings issued across America. But members of the hotel staff apparently didn’t see it that way. While he napped for two hours before the show opened, they disassembled the installation and put it in bags. Undeterred, he designed an installation under halogen lamps near the second-floor elevators. His career aloft, he soon had his first balloon installation in a gallery at Margaret Thatcher Projects in New York.

Asked if he has acclimated to the Big Apple, he said he had. “I’ve been told one sign of a New Yorker is if you give cab drivers directions,” he said. Busy with art projects and photography, Mr. Hackenwerth’s career will only grow, or, more precisely, expand.