When Niels Mikael Andersen was born on 3 July 1837, in Sejlstrup, Børglum, Hjørring, Denmark, his father, Anders Mikkelsen, was 35 and his mother, Johanne Nielsdatter, was 28. He married Karen Marie Andersen on 13 October 1863, in Vejby, Hjørring, Denmark. They were the parents of at least 2 sons and 5 daughters. He lived in Serritslev, Børglum, Hjørring, Denmark for about 10 years. He died in April 1883, at the age of 45.