James Morgan McKelvey Jr. is an American billionaire businessman recognized for co-founding Block, Inc., originally known as Square, Inc., with Jack Dorsey in 2009. He served as Square's chairman until 2010 and currently sits on Block, Inc.'s board of directors. McKelvey's contributions to Square included early hardware development, and the company's iconic card reader design was inducted into the Museum of Modern Art in 2011.
Beyond Block, McKelvey has a diverse entrepreneurial background.