 This fjord was mapped in 1932 during the Three-year Expedition to East Greenland led by Lauge Koch.In August of the same year it was surveyed by Gunnar Seidenfaden.Koch named it after Commander Emil Valdemar Asger Grandjean (1889–1948), then chief of the Royal Danish Navy Air Service

Grandjean Fjord opens to the east, between Cape Negri to the south and Cape Buch to the north.