A piece of American tennis heritage isn’t coming back to life—it was never dead, you see—but it is awaking from a slumber. Matthew Feuer purchased 1973-born Boast to revive the dormant brand.

Boast, the classic tennis brand founded in 1973, has become the official apparel sponsor of the Garden Cup, which takes place Dec. 4. Boast will be outfitting officials, event staff and ball ...