Serena Joy is neither serene nor joyful. Then again, Serena Joy isn't her real name. In a novel full of characters referred to by pseudonyms, Serena Joy seems to stand out because she's chosen her own: "Serena Joy" was her stage name. The narrator writes:
With everything to choose from in the way of names, why did she pick that one? Serena Joy was never her real name, not even then. Her name was Pam. (8.21)
That assertion is later undermined in the "Historical Notes" by one of the professors, who observes that neither of the men they think could have been the Commander had a wife with the name Serena Joy. Instead, it "appears to have been a somewhat malicious invention by our author" (Historical Notes.39). Well, the narrator had to amuse herself somehow, right?
Serena Joy has led a past life as a Gospel star and homemaking advocate. The narrator can remember a time when, young and beautiful, she sang and cried on cue on her Gospel television show. Later she becomes a motivational speaker:
Her speeches were about the sanctity of the home, about how women should stay home. Serena Joy didn't do this herself, she made speeches instead, but she presented this failure of hers as a sacrifice she was making for the good of all. (8.21)
Now she's no longer famous. She's stuck at home—in a kind of poetic justice, as the narrator points out (8.24)—and all she can do is knit, despite the fact that her hands are breaking down.
Serena Joy has no problem asking the narrator to betray the Commander and break the law by having sex with Nick so she has a better chance of becoming pregnant. But when she finds out that the narrator has broken other rules with the Commander, she's furious. She doesn't blame the Commander, just the narrator, even though the Commander is the one who started the affair. Perhaps Serena Joy can't afford to make accusations against the Commander. Still, her comment to the narrator is telling:
"Behind my back," she says. "You could have left me something." Does she love him, after all? (44.17)
With these statements—which lead the narrator to marvel at the possibility that Serena Joy could actually have feelings for the Commander—Serena Joy accuses the narrator of stealing "something" from her. Originally, though, that's what the narrator had wanted to do: steal a daffodil or a knife, something to remind herself of who she is. And the narrator admits that by spending time with the Commander, she does take something from Serena Joy:
I felt I was an intruder, in a territory that ought to have been hers. [...] I was taking something away from her, although she didn't know it. I was filching. (26.6)
Well at least Serena Joy, unlike most of the women in the novel, still has something left to take. Any outsider would see the narrator as the victim here. But after one of her humiliating sex acts with the Commander and Serena, the narrator stops to reflect, "Which of us is it worse for, her or me?" (16.21). We never know whether Serena Joy pauses to consider the same.