Gregory "Greg" Universe (né DeMayo) is the father of Steven Universe and was the romantic partner of the late Rose Quartz. He is the current owner of It's a Wash.

Greg struggled financially for most, if not all, of his adult life. However, in "Drop Beat Dad" he is awarded a royalty check and becomes a millionaire. Greg later uses some of the money to go on a trip with Steven and Pearl, where he and Pearl finally make peace with one another after having a strained relationship for decades. As Steven became more involved in his life as a Crystal Gem, Greg continued to support his son and learned to have more faith in him after previously showing concern for Steven's safety during his missions.

After living in his van for years, Greg moves into the Beach House in "The Future" when Steven decides to move out and find himself in the world.

Connie Maheswaran is Steven Universe's best friend-turned-girlfriend, and a member of the Crystal Gems who debuted in the episode "Bubble Buddies". After meeting Steven, she slowly began to learn about him, the Gems, and their past. Growing a strong bond with them, Connie decided that she wanted to help him and the Crystal Gems whenever danger arose in the Earth, training how to fight using a sword with Pearl since "Sworn to the Sword". She eventually becomes a skilled combatant and often aids the Gems during times of conflict.

Years later, Connie begins to devote most of her time to studying and applying to colleges. She sticks by Steven's side as he deals with his years' worth of suppressed trauma. After helping Steven cope, Steven and Connie decide to meet up with each other as she tours the country on college tours, and he tours the world to find himself. It is revealed that the two are officially dating by the end of the series.