As a widow, she had a seat in the regency government of her nephew Magnus, who reigned as king of both Sweden and Norway.

In 1300, Ingeborg's mother arranged her three-year-old daughter's engagement to Jon Magnusson, Earl of Orkney (died 1311).

In a 1312 double wedding in Oslo (another match arranged by her mother), Ingeborg married the Swedish king Birger's youngest brother, Valdemar, Duke of Finland, while her younger cousin Ingeborg, the only legitimate child of King Haakon V, married Birger's eldest brother Duke Eric.

At the imprisonment of her husband and brother-in-law, she and her cousin and sister-in-law, Ingeborg Håkansdotter, became the leaders of their spouses' followers.

On 16 April 1318, "the two duchesses Ingeborg" made a treaty in Kalmar with the Danish duke Christoffer of Halland-Samsö and archbishop Esgar of Lund to free their husbands and not to make peace with the kings of Sweden and Denmark before they agreed to this, and the two duchesses promised to honour the promises they gave in return in the names of their husbands.