Sweeney estimated that between the ages of 11 and 15, he spent over 10,000 hours teaching himself how to program using information on online bulletin boards, and completed several games, though never shared these with others.

As a teenager, he made a good deal of money by offering to mow lawns of wealthy residents in the area for half the price of professional services.

[6] For continued development, Sweeney sought out a business partner for Epic MegaGames, eventually coming to Mark Rein, who had just been let go from id Software.

[8] Since the real estate bubble collapsed in 2008, Sweeney has used his fortune to purchase large tracts of land in North Carolina, reportedly for conservation, becoming one of the largest private landowners in the state.

[9][10] As of December 2019, he has bought 50,000 acres of forest land including the Box Creek Wilderness, a 7,000-acre natural area that contains more than 130 rare and threatened plants and wildlife species.

[9] One of the motives to put Box Creek Wilderness under conservation easement was a condemnation lawsuit filed by a power company who planned to build a transmission line through the land.

"And for the whole Fish and Wildlife Service team's tireless efforts to preserve vital North Carolina natural areas in partnership with conservation-minded landowners like me.

When transferred the next year, the conservancy will manage the property as a nature preserve, conducting scientific studies in collaboration with Sweeney and offering guided hikes.

[14] In February 2012, Sweeney was inducted into the Academy of Interactive Arts & Sciences (AIAS) Hall of Fame for changing "the face of gaming with the advent of the Unreal Engine and the commitment of Epic, as a studio, to bring both consumer and industry-facing technology to new heights.

[11] At the Forbes Media Awards 2020, Sweeney was chosen as Person of the Year for building and turning Fortnite into a social network with his company, hosting online events such as Travis Scott's in-game concert which drew 28 million viewers.