Before the Crash
When Christian went missing in Australia she convinced Jack to go after him, saying he wouldn't get to say no "after what he did," in reference to Jack's causing Christian to lose his medical license. ("White Rabbit")
After Jack's return
After the return of the Oceanic Six, she was awaiting Jack at the runway. She was extremely glad to see that he had returned safely. Afterward, she attended Christian's funeral. She left when it was over and returned home to wait for Jack. ("There's No Place Like Home, Part 1")
Margo talked to Jack via cell phone after he landed at LAX. Jack was frustrated that his father's casket had been lost. ("LA X, Part 2")
Margo later called Jack as she was unable to locate Christian's will among his papers. After he arrived to assist her, she found it at last, but was puzzled by the mention of someone named "Claire Littleton". When she offered him a drink, Jack refused, leading Margo to say, "good for you." ("Lighthouse")
- Margo appeared in 3 episodes.
- One of her appearances was made solely by her flash-sideways counterpart.
- Margo appeared in one flashback episode ("White Rabbit"), one flash-forward episode ("There's No Place Like Home, Part 1"), and one flash-sideways episode ("Lighthouse").
- Her first and last appearances were Jack's first flashback and flash-sideways episodes.
- Margo is short for Margaret. Margaret is a Greek name for Pearl. 
- Margo's appearances were 75 episodes apart, the second longest gap after Tom Brennan's gap of 80 episodes. However, she is still the character with the longest gap between appearances played by the same performer, as Tom Brennan was played by different actors in each episode.
- For fan theories about these unanswered questions, see: Margo Shephard/Theories
- Why did both Christian and his father feel that Margo was the "wrong choice"?