He served in the Scanian War of 1675–1679 and during the following twenty years of peace worked to build up the Swedish Navy.

When the new fleet base was established at Karlskrona in 1681, he became governor of a new enlarged county, Kalmar and Blekinge län.

Hans Wachtmeister was also admiral general over the entire Swedish Fleet at the same time that he was a governor.

He was raised to the dignity of a count in 1687 with the name of Wachtmeister af Johannishus and introduced in the Swedish House of Nobility in 1689 as number 25 among the families with the title of count [Grevliga ätter] in the List of Swedish noble families.

His younger brother was Swedish field marshal Axel Wachtmeister, and his father-in-law was Rutger von Ascheberg.