Strengell was born in Helsinki, Finland, daughter of Finnish architect Gustaf Strengell and interior designer Anna Wegelius. She graduated from the Central School of Industrial Design in Helsingfors in 1929, then went to Stockholm where she assisted in the preparations for the 1930 Stockholm Exhibition. Strengell held several positions in Scandinavia, designing rugs, textiles and interiors. One of her earliest positions was as a designer at Hemflit-Kotiahkeruus where her mother, Anna, was director and responsible for starting a cottage industry in weaving for the farmers' wives. Strengell left Scandinavia for the United States in 1936.