Johnson was born and raised in Los Angeles, California. When she turned seven, Johnson split the rest of her time growing up in Phoenix, Arizona, and Portland, Oregon. She attended theUniversity of Arizona, where she majored in theatre. While pursuing her degree, she performed in a number of dramatic plays and was a member of the school's sketch and improv group,Comedy Corner. Johnson had supporting roles in such films as Role Models, The 40 Year Old Virgin, Transformers and In Her Shoes.