It’s a fine June day in New York City. Bill Ackman peels off his suit jacket in the afternoon sunshine, and hands it to a chauffeur parked outside his office in Manhattan’s Hell’s Kitchen. Wearing a crisp white shirt and a “Never Forget 9/11” blue cap, the 60-year-old billionaire sets out for a three-mile walk. He’s on a very personal errand, but Ackman is all business as he strides briskly through the city.

At a trim six-three, Ackman takes pride in his fit appearance, which he attributes to avoiding sugar and alcohol. He’s not shy about dispensing workout tips to his staff and discussing how many pull-ups he can do: “I’ll say 10,” he notes, adding, “I could do 100 if you give me enough time, though I’d have to rest between sets.” (If a pull-up bar had sprung up from the sidewalk, I have no doubt that he would have leaped upon it to make his point.)

If Ackman feels superhuman these days, it’s understandable: He has just turned his investment firm, Pershing Square, into a public company and simultaneously launched a publicly traded investment fund in an unusual double NYSE listing. The move caps a Wall Street odyssey that began in the 2000s, when he first made a name for himself making bold bets as a short-seller and an activist investor.