Mrs. Hagberg

Mrs. Hagberg was a teacher at McKinley High. It is not known if she specialised in a subject, but she appears in a teaching role throughout seasons two and three, often teaching members of the New Directions. She retires from her position in Nationals, the twenty-first episode of Season Three, and has not appeared since then.

She is portrayed by Mary Gillis.

Prom Queen
Mrs Hagberg was introduced in Prom Queen in which she is seen teaching Brittany, Mercedes, Kurt and Tina Home Economics before Artie, Sam, Finn, and Puck interrupt her class to sing Isn't She Lovely to Brittany.

I Am Unicorn
She returns in this episode, where it's revealed that she is also a Geography teacher. She is astounded that Brittany thinks that the capital of Ohio is O and that the president of the United States is will.i.am.

I Kissed a Girl
It is shown that she is also a Math teacher. When Puck raises his hand to answer a question, she tells him that he doesn't need to ask in order to go to the toilet. She is both astounded and sceptical when Puck tells her the right answer.

The Spanish Teacher
It's revealed that she also is a History teacher, and was forced into retirement due to memory problems. She is shown teaching the history of World War II, wrongly stating that Nazi Germany won and apparently took over the whole world.

Nationals
Mrs. Hagberg accepts an award for 40 years of service on the stage of the auditorium as she retires. She says she plans to kick her addiction to painkillers, as well as plugging her upcoming appearances on Intervention and Hoarders. This was her final appearance on the show.

Trivia

 * In The Spanish Teacher, it's revealed that she had been teaching for 40 years.
 * She was seen teaching a different subject every time she appeared on the show.
 * She is addicted to painkillers. (Nationals)
 * She appears in the music video for Moves Like Jagger/Milkshake in the "Sexuality" episode of the second season of The Glee Project.