Effi Briest
Effi Briest is the seventeen-year-old eponymous heroine of the novel. She is vain and is attracted to social status. She is soon married off to an older man.
Innstetten
Innstetten is the 38-year old husband who has married Effi. He doesn't give his wife much attention and goes away for weeks, leaving her in the middle of a society that has marginalized her. He later divorces her when he gets to know about her infidelity.
Major Crampas
Major Crampas is a womanizer who enters the scene later in the novel. He is a married man but is known for his infidelities. Effi finds herself getting attracted to him and they end up having an affair.
Later in the novel, Effi's husband gets to know of this affair and ends up killing Major Crampas in a duel.
Luise
Luise is a minor character in the novel who is told by a dying Effi to tell Innstetten that she regrets having the affair.