In Quentin Tarantino’s Reservoir Dogs, Harvey Keitel’s character uses the code name Mr. White.
The film assigns its gang members color-based pseudonyms so they can work together without learning one another’s identities. Mr. White is one of the robbers involved in the planned diamond heist, and he develops a protective bond with the wounded Mr. Orange after the operation collapses.
The code-name system is central to the film’s opening and to its investigation of trust. Mr. Pink, played by Steve Buscemi, is especially skeptical of the plan and of the other criminals. Mr. Blonde, Mr. Brown, and Mr. Blue complete the set of color names used by the group.
This question concerns Mr. White’s alias, not the actor’s name or the color of his clothing. Keitel plays Larry Dimmick, but the character is identified throughout the film by the assigned name Mr. White.