His parents were the sea captain Anders Börjesson Gathe and his wife Kerstin Larsdtr Styrman, daughter of a mill owner in Hjälm, Fjärås Parish.
[2] To protect Swedish shipping from pirates and to harm the enemy, in June 1710 the government of King Charles XII of Sweden gave Lars Gathe Letter of marque granting permission to seize ships from enemy nations including Denmark and Russia.
He had a great deal of early success with his galleon Lilla Jägaren, and as the volume of hijackings increased, many local sailors were quickly recruited to work the privateer ships.
He suffered from a hip injury that made him dependent on crutches and may not have spent much time at sea himself, instead directing the work from Gothenburg.
His wife Ingela Gathenhielm née Hammar (1692–1729), who he had married in 1711, succeeded him and expanded the various business enterprises.