The first one to use the name was in accordance to the book "Familien Heyerdahl" (inherited from my father in law, Halvor Christian H. - and full of handwritten notes) was:
Sven Haagenssøn Heyerdahl, born at Bismo 1691 and died at Holand 26.dec.1762.
He was corporal at Sondre Bergenhusiske Regiment 1710.
Capitaine des armes 1712.
Adjutant 1716.
Sec. lieutenant 1717.
Premierlieutenant 1719, and left the army 1739.
1711 he got, (at that time stationed at Fredrikhald, and then called himself HEYERSTAD) a child with Angerd Olufsdatter and was by 'Kontitorialretten' (the court) 5.july.1712 sentenced to marry her. The sentence was upheld by Overhofretten (higher court) 16.5.1713 (in the latest sentence by Overhofretten is the first time he used the name HEYERDAHL.) It does not look like he married her.
Sven became a few years later married Boel Pedersdatter Hagenberg. In accordance to himself they got 15 children, of which 11 is known.
He was the older brother of Mette Haagensdatter Heyerdahl.
(In other sources I have found that he also used the name 'von Heyerdahl - but the sentences is well documented on original documents - I guess both had a more military sound than Haagensson)

Som fellow!!

Regards
Kaare Sandvik
Norway