As a prince, Leopold is engaged to Princess Eva, but after meeting another woman, Cora, he chooses to marry Cora instead. However, when Eva discovers that Cora is pregnant with another man, she tells Leopold right away. Leopold has Cora removed from the palace, and eventually marries Eva, where they have a daughter named Snow. After his daughter is rescued from an out-of-control horse, King Leopold finds the woman who rescued Snow - Regina - and asks for her hand in marriage. Regina finds herself in a forced marriage when her mother, Cora, says that he can marry Regina. They get married, and Regina becomes queen, and although King Leopold loves Regina, he also loves his former late wife, Eva. One day, while taking a stroll, King Leopold comes across a magic lamp. After picking it up and dusting it off, he is surprised when smoke pours out of the lamp and forms into the Genie of Agrabah. Leopold wishes for the genie's freedom, and uses the second wish in order to give the third and final wish to the Genie himself.
Leopold welcomes the Genie to his palace where the Genie meets Leopold's daughter, Snow White, and also his wife Regina. However, when he sees Regina, he falls in love with her. Later that night, Regina excuses herself from King Leopold's birthday celebration. The Genie follows her, and Regina expresses her unhappiness in the marriage between her and Leopold. Regina eventually obtains two Agrabahn Vipers and tells the Genie that she plans on committing suicide, but the Genie stops her, and gives her an alternate solution - that King Leopold dies instead. The Genie orders the Agrabahn Vipers to kill the king, and they do, but not before Leopold sees the Genie looming over him. A funeral is later held for him.
- Eva White (deceased wife)
- Snow White (daughter)
- Emma Swan (granddaughter)
- Killian Jones (grandson-in-law)
- Neal Nolan (grandson)
- David Nolan (son-in-law)
- Henry Mills (great-grandson)
- Regina Mills (widow)
- Henry Mills Sr. (father-in-law)
- Zelena Mills (sister-in-law)
- Cora Mills (ex-fiancée / mother-in-law)
- Leopold is based on the king from the fairytale Snow White.
- S1, E11: "Fruit of the Poisonous Tree" (flashback)
- S1, E18: "The Stable Boy" (flashback)
- S2, E15: "The Queen is Dead" (flashback)
- S3, E18: "Bleeding Through" (flashback)