As J.Crew’s head menswear designer in 2008, Snyder oversaw the introduction of the Ludlow suit, whose slim, runway-indebted silhouette would define men’s tailoring for more than a decade to come.

But this week a most unexpected thing has been happening on Paris men’s catwalks — the stuffy old suit has come back. In show after show suits and tailored jackets have shaken off the toxic ...