Morris was born in 1989 in Philadelphia, Pennsylvania. He is the son of Thomasine "Angel" Morris and has four brothers, including twin brother and fellow NBA veteran Marcus Morris. Markieff and Marcus both played college ball at Kansas and were drafted 13th and 14th, respectively, during the 2011 NBA Draft. Markieff is nicknamed "Keef", a moniker given to him by his late grandmother Shirley. Morris is a big fan of the Dallas Cowboys. His favorite charity to work with is Helping Hands For Single Moms. Follow Morris on Twitter (@Keefmorris) and Instagram (@keefmorris11).