[1][2] In 1930, she published the authoritative two-volume Amagerdragter: Vævninger og Syninger on the history of costumes and textiles from Amager, an island adjacent to Copenhagen.

In 1897, in connection with an exhibition in Stockholm where she won a silver medal, she met Bernhard Olsen [da]}, director of the Danish Folk Museum.

[2] In the early 20th century, Mygdal designed a series of white damask tableware patterns for De Forenede Linnedvarefabrikker.

[4][5] In 1919, Olsen finally persuaded Mygdal to give up teaching at the Arts and Crafts School and move to the Folk Museum as an assistant curator.

In particular, she contributed articles to the Danish Tourist Board's yearbooks writing about costumes from various parts of the country, with titles beginning with Lidt om Dragter fra... followed by the region.