Luck might be underselling it. In Chicago’s business community, Pritzker has long been known for his affinity for cards. A poker book has been seen on the shelf of his Chicago office, and he’s been spotted sidling up to a table while traveling. That interest in poker goes beyond the personal. Pritzker teamed up with Jim Gray, who founded OptionsXpress, to start the Chicago Poker Challenge, a high-profile charity tournament that raised millions for the Illinois Holocaust Museum & Education Center, which Pritzker also helped establish. Though Pritzker no longer plays in the event, its reputation is legendary. It was...