The Giant appears to FBI agent Dale Cooper in visions, first right after Cooper has been shot in his hotel room. The Giant provides Cooper with clues about the murder of Laura Palmer, alerts Cooper that Laura's killer is in the process of murdering Maddy Ferguson and later confirms the identity of the murderer during a vision in the Roadhouse. Later on, he also warns Cooper that his love-interest Annie Blackburn should not enter the Miss Twin Peaks pageant (her winning the contest is a key element leading to Cooper's entering the Black Lodge and subsequently his downfall).
The Giant apparently inhabits an elderly Room Service Waiter of the Great Northern Hotel (played by Hank Worden). Also, the Giant wears a similar outfit to the Waiter (who in himself is a ghostly semi-conscious entity who almost never appears in a crowd or within the guests rooms of the Great Northern). In the final episode, when Cooper has entered the Black Lodge, both the Waiter and the Giant appear and the latter confirms their identity, stating: "One and the same".
Though the Giant's actions seem to be benevolent, he seems to be part of the evil Black Lodge, as he appears alongside of the Man from Another Place in the Lodge's waiting room. However, some have opined that the waiting room actually is a neutral location between the Black and the White Lodge. In his first appearance, the Giant refused Cooper's question of his whereabouts.
The track "What Does Your Soul Look Like, Pt. 1: Blue Sky Revisit" on DJ Shadow's 1996 album Endtroducing..... samples the voice of the Giant.
The Giant's words to Cooper in the hotel bedroom are sampled on the classic ambient album Substrata by Biosphere. The phrase "Sorry to wake you... I forgot to tell you something... The things I tell you will not be wrong..." appears in the song "The Things I Tell You".
In The Simpsons episode "Lisa's Sax", Homer Simpson is seen watching Twin Peaks in which The Giant is dancing with a white horse. Homer remarks, "Brilliant! (pause) I have absolutely no idea what's going on."