We first encounter Jordan Baker in Chapter One, when Nick sees her in the Buchanan's home, sitting next to Daisy, on an enormous couch.
The younger of the two was a stranger to me. She was extended full length at her end of the divan, completely motionless, and with her chin raised a little, as if she were balancing something on it which was quite likely to fall. If she saw me out of the corner of her eyes she gave no hint of it — indeed, I was almost surprised into murmuring an apology for having disturbed her by coming in.
... At any rate, Miss Baker’s lips fluttered, she nodded at me almost imperceptibly, and then quickly tipped her head back again — the object she was balancing had obviously tottered a little and given her something of a fright. Again a sort of apology arose to my lips. Almost any exhibition of complete self-sufficiency draws a stunned tribute from me.
It is clear that Nick is slightly intimidated by her, almost constantly wishing to offer her an apology for having invaded her space.
At this point Miss Baker said: “Absolutely!” with such suddenness that I started — it was the first word she uttered since I came into the room. Evidently it surprised her as much as it did me, for she yawned and with a series of rapid, deft movements stood up into the room.
When Jordan speaks, she seems to be just as surprised as he about her talking:
I looked at Miss Baker, wondering what it was she “got done.” I enjoyed looking at her. She was a slender, small-breasted girl, with an erect carriage, which she accentuated by throwing her body backward at the shoulders like a young cadet. Her gray sun-strained eyes looked back at me with polite reciprocal curiosity out of a wan, charming, discontented face. It occurred to me now that I had seen her, or a picture of her, somewhere before.
“You live in West Egg,” she remarked contemptuously. “I know somebody there.”
“I don’t know a single ——”
“You must know Gatsby.”
Jordan is the one who makes Nick aware of a problem between Daisy and Tom, when she gossips about the continuous phone calls Tom seems to be receiving at home from some mistress in New York, causing Daisy a fair amount of anxiety.
During his visit, Nick also has some faint recollection of Jordan when he finds out that her surname is Baker. It was something unpleasant that he had heard, but he could not recall anything. He discovers that she is a reasonably well-known professional golfer.
We next hear of Jordan in Chapter three when Nick meets her at one of Jay Gatsby's parties:
I was on my way to get roaring drunk from sheer embarrassment when Jordan Baker came out of the house and stood at the head of the marble steps, leaning a little backward and looking with contemptuous interest down into the garden.
The two of them listen to some of the guests gossiping about Jay Gatsby and she later invites Nick to join her party at supper. Much later Jordan is summoned by Gatsby's butler and she spends an hour with him. She later tells Nick:
"I’ve just heard the most amazing thing,” she whispered. “How long were we in there?”
“Why, about an hour.” “It was — simply amazing,” she repeated abstractedly. “But I swore I wouldn’t tell it and here I am tantalizing you.” She yawned gracefully in my face: “Please come and see me. . . . Phone book . . . Under the name of Mrs. Sigourney Howard . . . My aunt . . .” She was hurrying off as she talked — her brown hand waved a jaunty salute as she melted into her party at the door.
Nick and Jordan lose touch for a while but they later meet again and it is then that he remembers what she had done and that it had been quite a scandal: she had been accused of cheating in a tournament. He realises that she is quite dishonest but does not mind. He enjoys spending time with her. in all the papers: she had cheated during a golf tournament.
In chapter four Jordan tells Nick about Jay's passion for Daisy. She divulges the their history and informs Nick that Jay would like to arrange a meeting with Daisy at Nick's house and that Nick should invite Daisy over. She tells Nick:
“He wants to know,” continued Jordan, “if you’ll invite Daisy to your house some afternoon and then let him come over.”
Daisy, however, should not know about this arrangement.
We encounter Jordan again in chapter seven when she, Nick, The Buchanan's are at the Buchanan home and later go to Tom's apartment in New York. A huge argument ensues between Tom and Jay, whereupon Jordan and Nick wish to leave, but they stay nevertheless. On their journey home, Daisy, driving Jay's car, accidentally kills Myrtle Wilson, Tom's mistress. Nick is later so disgusted by them all, that he ignores Jordan and leaves.
In chapter eight, Nick and Jordan have a brief conversation and he is quite abrupt with her, telling her that he could not meet her that afternoon:
We talked like that for a while, and then abruptly we weren’t talking any longer. I don’t know which of us hung up with a sharp click, but I know I didn’t care. I couldn’t have talked to her across a tea-table that day if I never talked to her again in this world.
Finally, we read about Jordan in chapter nine. Jay has been shot and killed by Mr Wilson, who suspected that it had been Jay that she had been seeing and that he had driven her over, all suggested by Tom Buchanan. Nick goes to see her one last time, to tidy things up, for he did not want to leave any loose ends:
I saw Jordan Baker and talked over and around what had happened to us together, and what had happened afterward to me, and she lay perfectly still, listening, in a big chair.
She was dressed to play golf, and I remember thinking she looked like a good illustration, her chin raised a little jauntily, her hair the color of an autumn leaf, her face the same brown tint as the fingerless glove on her knee. When I had finished she told me without comment that she was engaged to another man. I doubted that, though there were several she could have married at a nod of her head, but I pretended to be surprised. For just a minute I wondered if I wasn’t making a mistake, then I thought it all over again quickly and got up to say good-bye.