He was the 6th State Treasurer of Wisconsin, served in the American Civil War as a Union Army officer, and was wounded at Gettysburg.

He was commissioned captain on September 9, 1862, of Company F in the German American 26th Wisconsin Infantry Regiment as it organized at Camp Sigel in Milwaukee.

At the Battle of Gettysburg, the XI Corps was ordered, during the first day of fighting, to proceed north of the city and establish a defensive position on Oak Hill.

In 1868, Baetz was a delegate to the Republican National Convention in Chicago that nominated Ulysses S. Grant for President of the United States.

He was elected State Treasurer of Wisconsin in 1869 alongside fellow Gettysburg veteran, Governor Lucius Fairchild, and was re-elected in 1871.