That year he commanded the military escort to Native Americans, including Chief Cornplanter, at the Treaty of Fort Harmar near Marietta, Ohio. While stationed at Fort Harmar, Ziegler married Lucy Anne Sheffield on February 22, 1789. Sheffield was a native of Rhode Island, and had come to Marietta with her widowed mother, who was a shareholder in the Ohio Company. The Zieglers did not have any children. In 1790 Ziegler was a part of Harmar's campaign against the Native American confederacy in Ohio, which ended in defeat and retreat to Fort Washington. Ziegler was a witness at Harmar's court of inquiry: he supported his commander and blamed the debacle on undisciplined militia, inadequate supplies, and poor logistics. Commissioned a major in the First American Regiment on October 22, 1790, the next year Ziegler accompanied General St. Clair in another expedition into the Northwest Territory, which met with even more disastrous results at the Battle of the Wabash. Ziegler performed well, covering the retreat of the fleeing Americans. Ziegler was placed in command of the western forces when St. Clair was recalled for a court of inquiry. Once again Ziegler was called to testify, and again he supported his commander. Disturbed by disputes and jealousy in the officer corps, he resigned from the army on March 5, 1792. Ziegler settled near Cincinnati, trying his hand at farming before opening a general store in the town. In December 1799, after hearing the news of the death of President Washington, Ziegler was a pallbearer in a mock funeral held for Washington, one of many such ceremonies performed around the country. After the rapidly growing settlement of Cincinnati was incorporated as a village in 1802, Ziegler was elected as mayor, then known as "President of the Council". He was unanimously reelected for a second term in 1803, but declined to run again in 1804. He was thereafter elected as commander of the local militia and held other public offices, including serving in 1807 as the adjutant general of the Ohio Militia. He was a wealthy man when he died in 1811. He was buried in Cincinnati. As the city grew, in 1844 his remains were transferred to another cemetery in the city. Several years later his remains were moved once again to lie with his wife in Woodland Cemetery in Dayton, Ohio. Cincinnati's Ziegler Park, at Sycamore Street between 13th and 14th Streets, was named for him by Over-the-Rhine Germans.