In a roomful of mostly builders, developers and planners, Frank J. McKee Jr. stood out - not just because of the silver stud earring he wore, but because of his tender age.

At 24, he was by far among the youngest - if not the youngest - of the couple of hundred attending the breakfast meeting of the Delaware Valley Smart Growth Alliance.

He is also the least senior at his family's development and building company, the McKee Group, but not by much. His sisters, Kate Black, 30, and Jenni McKee, 32, also work there. The trio represent a literal fresh face for a business their grandfather, Frank A. McKee, started 60 years ago.

Their father, Frank J. McKee, is counting on them to contribute fresh ideas that will not only sustain but also grow the business long after he takes a back seat. (At 58, he's not willing to say he will ever formally retire, noting that his father had "died in the saddle" at 85.)

That was in 2001 - five years before any of Frank A. McKee's grandchildren had made a career decision to follow in his footsteps.

That they have chosen to do so is increasingly rare. Had they opted instead to join the ranks of offspring of business owners who decide to chart their own career course, few could blame them.

As Frank J. McKee Jr. recalled, the reaction of classmates at Drexel University to his plans to go to work in construction during a recession when virtually all new building is at a halt was: "Are you nuts?"

He graduated last spring with a business degree, having majored in entrepreneurship. At the McKee Group, he is an acquisition associate, which means he scours the region for buildable land to buy. For McKee, the region includes Pennsylvania, Delaware and Maryland - and a 330-slip marina in Wildwood, an impulse buy years ago by Granddad McKee, who snapped it up at an auction.

Jenni McKee was the first of the three grandchildren to join the McKee payroll. That was in May 2006, after she had picked up a master's degree in communications and management from Simmons College in Boston and had worked for eight years as a college administrator, mostly at Simmons. There she ran service-learning programs, which combine classroom instruction and community service.

Then, she said, "I started wanting something different."

Music to her father's ears. Not that Jenni McKee was willing to come rushing home to just anything.

"There were a lot of job offers [from her father] but finally a communications position opened, and that's when I knew it was the right time," she said.

At McKee, where she is vice president of communications, she runs the Web site, works in sales and marketing and, just recently, started in a management position in the company's manufactured-housing division.

Not that the family business was ever something that was separate from their lives.

"It was a part of our growing up," Jenni McKee said. "We all had summer jobs. One summer we spent in the homes picking up trash - for an entire summer."

And there were loads of weekends spent "all packed in the car driving around looking at houses with my dad," she said.

Kate Black assures it was not all drudgery for the McKee three - thanks to the golf cart at the Elkton, Md., self-storage facility the company owned when the grandchildren were younger. The McKee Group now has six such complexes. Intended to make getting around the storage facility to check on the units easier, the golf cart became a much-adored amusement ride.

Now, she is into much headier stuff as associate counsel at McKee.

She joined the company two months after her sister, in July 2006. After graduating from Villanova University law school in 2004, Kate Black went to work for Saul Ewing L.L.P., of Chesterbrook, where she specialized in real estate transaction law.

"Around 2006, housing was growing and growing, and [McKee] was growing and my dad was calling saying, 'When are you going to come here? When are you going to come here?' " Kate Black said. "It just seemed like the right fit and the right time."

Now her world involves drafting residential and commercial leases and then some.

"Our dad has this philosophy about training: You don't come in from the top and expect to be able to run everything. You've got to get your hands dirty and learn the business."

That has led to the management position for Jenni McKee in McKee's manufactured-housing division and for Kate Black involving the company's 550 units of apartments and four office buildings. Each of the women is shadowing managers and also expected to come up with her own ideas for improving business. Frank J. McKee Jr. has not been with McKee long enough for management consideration, he said. But he serves on two committees: one dedicated to making all of the company's operations and assets environmentally friendly, and the other focused on generating ideas for future growth.

If he has his way - and the market cooperates - McKee's future will include mixed-use communities built around rail stations known as transit-oriented development, in which houses are heavily into green technology. Such communities are gaining a following among young professionals such as Frank J. McKee Jr. and his sisters and empty nesters.

Odd as it may sound, the constant at McKee, based in Springfield, Delaware County, has been its commitment to diversification.

What started as a heating and air-conditioning company formed by Frank A. McKee and brother-in-law Joseph McHale, branched into apartment building for the elderly after McHale's death in 1960. That set the stage for what would become a later emphasis on active-adult communities that originated with Frank J. McKee in the late '70s. After that came his idea for stretching even further into the self-storage business.

With four active-adult communities totaling 1,600 homes in development and another four with a total of 680 homes on the horizon, the company is focused now on making construction adjustments to meet the needs of baby boomers. ("We started putting bars in the clubhouses," Jenni McKee offered among several examples.)

All admit this is a trying time to be in the development business. But Dad McKee, who "always hoped that one of my kids would come into the business" but never thought all three would, said he would not have wanted them to start their real estate careers at any other time. Seriously.

"If young people came into this business in 2000, 2002, 2003 and spent their career in nothing but an up market, they really wouldn't learn the core of running a company and figuring things out and really working as hard as you can possibly work . . . to stay ahead of the curve," he said.

His daughters - one of them a mother and the other hoping to be one - said their biggest worry was balancing business and family responsibilities. Frank J. McKee Jr., who is single, said his greatest concern was "ensuring that we keep everyone motivated and on a positive level toward the future, reassuring people that real estate cycles come and go and that we can get through this."

There is one thing he can ensure about the future, he said. His ear-piercing days are behind him.

"I was 18," he said. "It was a phase."

Contact staff writer Diane Mastrull at 215-854-2466 or dmastrull@phillynews.com.