- Episode 2x15, Maternity Leave
She appears in flashes of Claire's memory. She helped Claire escape from the Others, but Claire doesn't remember very much about her.
- Episode 2x22, Three Minutes
Alex, Pickett, and Mr. Friendly have Michael by a fire. Mr. Friendly goes out to the scene we'd seen previously (Ep: 2x11, The Hunting Party) where Mr. Friendly had confronted Jack, Locke, and Sawyer. When Mr. Friendly says, "Bring her out, Alex," Alex doesn't do it, so Pickett pushes Kate out to Mr. Friendly.
They hear gunshots and Alex tells Michael, "It's okay. He's just delivering a message. He has to scare your friends to do it." Later, Alex asks, "Is Claire okay? Did she have the baby? Is it okay? Is it a boy or a girl?"
- Episode 2x23, Live Together, Die Alone
Alex, along with a group of Others, bring Kate, Jack, Sawyer, and Hurley to a dock where they talk to non-Henry.
- Episode 3x2, The Glass Ballerina
Alex hides so that she can talk to Kate with no one else knowing. She asks if Kate is being kept in the cage. She wants to know if Kate has seen a guy, about her age, named Karl in the cages, but Kate says no. Alex tells Kate that she's wearing Alex's dress, but to keep it, that it looks better on Kate. Then she runs off before Kate can ask her anything.
- Episode 3x6, I Do
Alex breaks onto the compound and uses a sling shot to drop a couple of guys. She points the sling at Pickett and says she wants to talk to Ben. As they are dragging her away, she yells to Kate not to believe them. She says that they will kill Kate's boyfriend the way they killed Alex's boyfriend.
When he goes into surgery, Ben asks Juliet if Alex asked about him and she says no.
- Episode 3x7, Not in Portland
Alex saves Kate and Sawyer from the Others. She tells them she will help them get to the other island if they help her free her boyfriend, Karl. The three go to where Karl is and break him out. Alex prepares to go on the boat with Karl, Sawyer, and Kate, but Juliet says that she has to stay, or Alex's father, Ben, won't let Karl live. Alex says goodbye to Karl and tells him that she will see him soon.
- Episode 3x9, Stranger in a Strange Land
Isabel tells Alex that she should check on her father.
Alex goes to see Jack in the cage. She breaks the camera with a rock so that no one is listening and Jack can tell her the truth. She is distressed and wants to know why Jack saved Ben after all that he had done to Jack and the other crash survivors. Jack says he did it because he said he would. Alex struggles with her love versus her disgust of Ben.
Alex helps Jack see Ben, but she hovers in the doorway instead of going into the room. Then Alex takes Jack to Juliet's hearing where she gives Isabel a note from Ben.
- Episode 3x13, The Man From Tallahassee
Alex wonders who her father is talking to and even though Ben says not to come in, she does and is taken hostage by Locke. When Tom knocks at the door outside, Locke hides himself and Alex in the closet.
Locke wants Alex to go get Sayid's bag, and Ben sends her. When she sees Sayid, he tells her that she looks like her mother and she says that her mother is dead. Sayid says, "I'm sure that's what they told you."
Alex brings the bag to Locke and then he has her take him to the submarine. Then he lets her go.
- Episode 3x20, The Man Behind the Curtain
When Alex hears that Locke and Ben are going to see Jacob, she gives Locke a gun and tells him that he's going to need it.
- Episode 3x21, Greatest Hits
When Ben returns to camp, Alex wants to know when he got back. She asks about Locke and Ben gives her back her gun. She listens as Ben tells Richard that Locke had an accident and that they are going to the Losties' beach camp now.
Alex runs through the jungle to where Karl is hiding and tells him to go to the Losties and warn them.
- Episode 3x22, Through the Looking Glass
Alex asks Ben where he's going and he says he is going to talk to Jack and Jack's people. Alex says she's going with him and is surprised when Ben says she can.
Later, as the two walk through the jungle, Ben talks to Mikhail on his walkie-talkie. Alex is upset when Ben tells Mikhail to kill Charlie and shocked when he says to kill Bonnie and Greta too.
While they wait for Jack, Alex asks why Ben let her come and he says that he is delivering her to her new family. He was hard on Karl because he didn't want him to get Alex pregnant. But Alex betrayed him.
Alex waits while Ben talks to Jack. When they return, Alex sees that Ben was beaten. Alex kneels beside him and Rousseau comes and stands next to her. Ben says that Rousseau is Alex's mother.
- Episode 4x1, The Beginning of the End
Alex and Karl decide to go with Locke's group.
- Episode 4x2, Confirmed Dead
Ben wants to talk to Alex, to tell her something, but Alex doesn't want to listen. Karl defends Alex, but Ben baits him and Karl pulls a gun on Ben. Sawyer tells him to take it easy and to take a walk.
Later, Karl tries to help Rousseau take Alex away when Locke is going to shoot Ben.
- Episode 4x8, Meet Kevin Johnson
Ben tells Alex that the people on the freighter are coming for him and they will use her to get to him. He tells her to go to the temple and Rousseau thinks it's a good idea. Alex, Karl, and Rousseau head to the temple with the map Ben gave them.
They stop for a break and Alex and Karl talk about Ben. Karl is shot and dies. Rousseau grabs Alex and they duck by a tree. Rousseau tells Alex that she loves her and they have to run. When Rousseau gets up to run, she is shot and killed.
Alex stands and puts her hands up, yelling that she is Ben's daughter.
- Episode 4x9, The Shape of Things to Come
As their prisoner, Keamy and his men force Alex to disable the security fence. She types in a panic code to warn Ben.
Keamy uses Alex to get to Ben, but Ben won't budge. Ben says she's not his daughter, she's just a pawn and he doesn't care if they kill her. It was a bluff and he is devastated when Keamy shoots Alex.