Mortensen Last Name: Meaning and Heraldic Roots

The last name Mortensen is one of the recorded forms of Martensen, a German family name. At root, the name means “Son of Martin”.

Family crest and blazon

Heraldry is personal: arms associated with the Martensen surname were borne by specific families, and sharing the name does not mean sharing the blazon.

How the spelling arose

Spelled with “o” instead of “a”, Mortensen shows how the same name was heard and written differently. Regional accents shaped spellings long before dictionaries fixed them. Other spellings include Mortensson, Martienssen and Martinsen.

In the 2010 US Census, 11,013 Americans gave Mortensen as their last name (rank 3,282). For the full story, order the Mortensen surname pack.