Editors' Note: This is the first in a series of articles about change-makers—the thought-leaders who've profoundly affected the business of veterinary practice and whose vision could change average practitioners' career path, business model, or workday in the future.

Dr. Scott Campbell is standing at a big window in his second-floor office at Medical Management International (MMI), the parent company of Banfield, The Pet Hospital. Across Tillamook Street the original Banfield hospital sits in the elbow of three busy roads on this blue-collar side of Portland, Ore. The sky is heavy, the asphalt slick with rain. If the clouds part he'll be looking at Mount Hood.

Banfield timeline

The story begins with a problem: Dogs destroy the grass in dog parks. Then comes the need for evidence. His associates studied the way dogs behave and discovered that they run back and forth along fences. Now comes the solution: Build sidewalks next to the fences. That way the turf doesn't turn to mud in the summer. The design, Dr. Campbell says as a small dog romps along the fence below, obviously works.

But the park's crown jewel is the fountain and wading pool in the middle of the four diamond-shaped runs. Both dogs and children frolic in the water in summer, so chlorine is required to protect the kids. But chlorine is bad for dogs. This is the kind of dilemma Dr. Campbell obviously loves. He lays out the problem, pauses, then delivers the punch line.

"So ... we dug a well," he says.

The well ensures that the water is always fresh—no chlorine necessary. The earth washes the water clean as it seeps back into the aquifer. As Dr. Campbell will say a dozen times today, "Everybody wins."

No surprise that Dr. Campbell sees this park as a model for dog parks in cities everywhere. He is equally convinced that Banfield, The Pet Hospital, has captured the model of the future for veterinary practices everywhere.

Of course, not everyone agrees. Dr. Campbell's ideas have never been conventional, safe, or understated. In Banfield's early years, the hue and cry of objection was cacophonous. But no one can dispute the effect he has had on the profession of veterinary medicine. He may be a self-described introvert, but he is not shy about listing the changes he thinks Banfield has fostered. His voice rises when he describes how the Banfield model helps veterinarians build careers and private lives at the same time. In many ways, he has rewritten the rules of veterinary lifestyle for the new century.