With jobs more plentiful these days, Matt Tait could easily find full-time work. But he wanted to focus on his wooden toy business and took a part-time gig at Team Detroit, Ford Motor’s advertising agency.

It’s a win-win. Tait’s boss is happy to have him because the 31-year-old graphic designer’s outside activities make him more creative. And Tait has time to run Tait Design Co., which sells balsa airplanes and wooden yo-yos of his own design.

Six million Americans like Tait are choosing to work part time, according to the U.S. Bureau of Labor Statistics. Typically young and college-educated, they’re not doing so because personal or economic circumstances forced them to. Rather, many are abandoning the traditional career path their parents took and working just enough hours to pay the bills or pursue a passion: toy making, puppetry, nonprofit advocacy. Their numbers have increased 12 percent since 2007, according to the BLS, a shift with broad implications for hiring practices.

“The workforce of the past was organized around company,” says Chauncy Lennon, who runs JPMorgan’s workforce initiatives and is studying flexible working arrangements. “The workforce of the future is organized around the worker. If we can’t find the right people, it’s going to hurt our bottom line.”

Businesses keen to tap this pool of well-educated workers are tailoring jobs to individuals—not the other way round. Team Detroit is letting Tait take a few months off later this year so he can focus on filling orders in the holiday season. Deloitte Tax is breaking projects into pieces and parceling some of them out to teams of part-timers. Customer-service giant TeleTech Holdings texts job alerts to a pool of workers, who tell bosses if they’re available or not.

More than 20 million Americans are working less than 35 hours a week for “non-economic reasons,” according to the BLS. In other words, it’s a deliberate choice—not because they can’t find full-time jobs. Two-thirds of the 20 million are working part time because they have family obligations, are attending school, or are semiretired.

The final third are the 6 million this story focuses on—many of them people, like Tait, who are working part time because they don’t want to commit to one job or employer. No one knows if the trend will endure or will become more widespread. But if more and more Americans choose this career path, companies will have to adapt, says John Challenger, who runs Challenger, Gray & Christmas, a Chicago human-resources consulting company.

Tait says he made good money for four years as a full-time graphic designer before joining Team Detroit part time.

“Something was missing,” he says. “I always wanted to build my own business.”

In interviews, workers in their 20s and 30s describe watching their parents commit to one employer for their entire careers, only to lose their jobs after the financial crisis. Or working in a job they didn’t particularly like to pay the bills or chase the American Dream. They don’t want to be that person.

Andria Caruthers, 27, who graduated in May from the University of Missouri with dual masters degrees in journalism and public health, says she doesn’t plan to seek a full-time job. She’s going to look for freelance work in digital marketing in the health-care field and live with her parents for now. Her parents both lost their jobs in 2009 during the recession after long careers in white-collar manufacturing jobs.

“My parents kind of dedicated themselves and were loyal employees for a really long time and kind of had stressful lives,” Caruthers says. “And looking back, I see them, the way they really threw themselves at their careers, and it kind of turned on them. I want more of a balanced life. I want to have a healthy work-live balance.”

“I’m making a sacrifice lifestyle-wise to do what I want.”

Like Tait, Alex Stuart worked full time before deciding part-time was a better fit. The 24-year-old Duke graduate with a degree in history spent about a year working in Singapore for the American Chamber of Commerce. He now works two part-time jobs that satisfy a longtime passion: recruiting talent for Major League Soccer in the U.S. Stuart lives with four other guys in Manhattan, scrimps on travel costs by walking to work, and cooks for himself to reduce food expenses. The Web allows him to scout players all over the world from his computer.

“I’m making a sacrifice lifestyle-wise to do what I want,” Stuart says. “As time goes on, and my generation gets older, I think this path could become more commonplace.”

By 2020, as much as 40 percent of the workforce may toil part time, according to Mike Preston, Deloitte’s chief talent officer. The company has created what it calls Deloitte Open Talent to network with and identify workers who are opting to forgo full-time work for some other arrangement. Last year about 8,000 of the almost 70,000 workers at Deloitte were part-time. Companies focused solely on traditional full-time hires are missing out, Preston says.

Team Detroit has many people who work only on short-term projects, and flexibilty has become a watchword, says Traci Armstrong, senior vice president and talent acquisition manager. She cites a freelancer with apartments in Detroit and Santa Monica who picks her city based on the weather. She doesn’t want a full-time job, Armstrong says.