The more the pure fashion drawing stepped into the background in his graphic work from 1960 onwards, the more Gerd Grimm turned to the theme of "Girls". After supplying six portraits of young women as motifs for a calendar to the Waldkirch folding box manufacturer for the first time in 1959, the demand for such graphic sheets increased rapidly in the following years. "Grimm's girls" (Grimms Mädchen) soon became his trademark and gained him a legendary reputation among experts.

At the age of eighty he drew girls so that Gerd Grimm, whose portraits of girls make up by far the lion's share of his artistic work, could almost be described as the graphic artist of the "Fräuleinwunder". His models were always amateurs (mostly students from the University of Freiburg or the Pädagogische Hochschule) because Grimm appreciated their uneducated way of giving and moving, which he could not find in trained models any more. Again and again Grimm experimented with unusual perspectives in his portraits, e. g. with an oversized hand at the lower edge of the picture or in a mirror situation. He was also particularly attracted by pair constellations, because the different characters created a special dramaturgical tension that required appropriate aesthetic implementations and solutions.