Nairobi, Sept. 20 -- Before answering, Donald Wangunyu pauses. His eyes shoot up to the left, searching the corners of his brain, looking for the right words. When he finds them, it's an avalanche, a problem of abundance. But when the CEO of FourFront Management is not thinking, he is doing stuff. Having conversations with the dead, a la the philosopher Zeno of Citium. Or wearing bow ties, his dash of magic, or madness, depending on who you ask. He is a bit of a craftsman himself. "I am redesigning my wedding ring," he says.

He is also a systems man. Even as we take a walk at his home in Nairobi's Kitisuru, where he is supervising some construction projects, his movements seem practised, like those of someone who did everything according...