Sandvig was born on a farm near Chaffee, Cass County, North Dakota, USA, on 25 November 1911. Her parents were Gottlieb William Sprunk (1861–1956) and Augusta Amelia Nienas (1873–1966), both German immigrants. She was confirmed in Chaffee Evangelical Church. She grew up on a farm near Chaffee, where her family had pigs and chicken. She attended classes in rural schoolhouses and would take turns with her siblings staying home from school on Mondays to help her mother with housework

After graduating from Chaffee High School in 1928, she received her teaching certificate from Valley City State Teachers College (now Valley City State University). At the age of 19, she started working as an educator, picking up her students in a horse and buggy. She taught at a school in Logan County for one year and at the Bandy School near Leonard for seven years. It was during this time that she met Edwin Sandvig, whom she married in the Chaffee Evangelical Church in June of 1938. Following the marriage, the couple focused on farming. The couple had no children but fostered several children. They farmed south of Embden before moving near Leonard. They became members of the Lutheran Church in Leonard. She served as the Sunday School superintendent for a decade, led the Leonard Starlets 4-H Club for twelve years, and was a dedicated member of the Hollyhock Homemakers for over fifty years.

In 1973, after her husband developed bronchial asthma, they made the decision to sell their farm in 1974 and moved into an apartment in Leonard. Over the course of fifteen years, they spent their winters in Texas and Arizona. Her husband passed away in 1991, but she continued to reside in the apartment. Throughout her life, she enjoyed reading, sewing, crafts, spending time with her family and friends, and she actively participated in her church during her younger years. She loved poetry and was frequently called upon to give readings on various occasions. Additionally, she enjoyed traveling, having made three trips to Germany, two to Hawaii, and two to Alaska. She also spent time with her nephew Wes at their lake home in Montana and at their residence in Phoenix.

At the age of 103, she relocated to Bethany Homes Assisted Living, where she enjoyed playing bingo, attending chapel, and participating in Bible study. Over the years, her hearing diminished, and her eyesight weakened. Nevertheless, she continued to play the piano.

Helene Sandvig passed away at Bethany On University Nursing Home in Fargo, North Dakota, USA, on 5 December 2023, at the age of 112 years, 10 days.