Schwalbe was born in Struer, Midtjylland, Denmark on 10 March 1914 as one of six children. At 12 years old, she started work as a nanny for a local farming family, where she learned to cook, clean, and the art of housekeeping. Her mother died aged 49.

At the age of 15, Schwalbe moved to Holstebro to work as a housekeeper. The neighbour’s son would later become her husband in 1938; the couple had three daughters. Schwalbe returned to her hometown of Struer in 1945, bringing her family with her. Her first experience in drinking beer was not until the age of 70, after being convinced to taste it by her son-in-law.

Schwalbe was widowed in 1981. She had worked as a seamstress, and enjoyed needlework even after her retirement. She continued knitting into her centenarian years. Until the age of 100 when she started using a walker, she could walk with no assistance.

At the age of 104, Schwalbe developed heart problems and became one of the oldest people in the world to have a pacemaker fitted. She still lived independently at the age of 109. As of 2023, her younger brother Bertel was alive at 103. Two other siblings of hers lived to 103 and 100 respectively.

Schwalbe celebrated her 110th birthday in a Struer apartment complex in March 2024, surrounded by her children, grandchildren and great-grandchildren. She stated that she dreamt of having a great-great-grandchild. Her eldest child, then aged 85, was living in a nursing home.