The Meijerfeldt family came from
Livonia. Johan August Meijerfeldt the Younger was born in
Stralsund in
Swedish Pomerania on 4 May 1725. He began a military career early in life. In 1737 he was already serving in a regiment in his hometown. In 1744 he was promoted to the rank of captain, and the following year received royal permission to leave the country to fight in the
War of the Austrian Succession on the side of Austria, first against
Prussia and later against
France. He participated in the
Battle of Soor and the
Battle of Kesselsdorf, and in 1746 he was taken prisoner by French troops. After his release he returned to Sweden. Back in Sweden he became a confidant of Queen
Louisa Ulrika and aided her in trying to raise funds abroad for her failed coup d'etat in 1756. After the failed coup, Meijerfeldt was briefly arrested and questioned but did not suffer any serious repercussions. However, he again left Sweden to fight in the
Seven Years' War, this time on the side of
Brunswick. He participated in the
Battle of Hastenbeck in 1757. Following Sweden's entry into the war, he returned to Sweden and joined the Swedish army. He commanded forces fighting around
Peenemünde,
Güstrow and
Wolin during the subsequent
Pomeranian War. In 1759 he was promoted to the rank of
lieutenant colonel. He was politically engaged in Sweden during the 1760s, -70s and -80s. With the outbreak of the
Russo-Swedish War in 1788, he returned to active military service and initially commanded a brigade attempting to take
Hamina, an effort which derailed due to a lack of supplies and ammunition. Following the
Anjala conspiracy, Meijerfeldt was given command of the forces around Anjala. In December 1788 he was given the overall command of all land forces in Finland in the absence of the king. In this capacity he reconquered
Karkkila in July 1789, and managed to thwart further Russian gains in Finland. When the war ended with the
Treaty of Värälä, he was promoted to
field marshal. Soon after the war he retired, in opposition to the increasingly authoritarian politics of King
Gustav III. He spent most of his remaining life at his family estate in in Pomerania. He married
Louise Meijerfeldt in 1763. He died in Stockholm on 21 April 1800. ==Awards and decorations==