Earlier, he served as a Union Army officer during the American Civil War, and lost his right leg due to wounds.

His father died shortly after he was born, his mother remarried and he was raised at the home of his step-father until he was about fourteen years old, receiving a liberal education.

[1] At age 14, he went to work a team of mules on the Erie Canal, but returned home after three years and apprenticed as a paper-strainer under his step-father, who then had an extensive business in that industry.

[1] In April 1861, as reports arrived of the attack on Fort Sumter, Conner quit his job with the city and volunteered for service with the Union Army.

[2] In January 1864, he was commissioned as second lieutenant of Company C. In that capacity, he was wounded in the face and neck at the Battle of Poplar Springs Church in the Richmond–Petersburg campaign.

[1] While recuperating in the hospital, he mustered out of federal service and received a new appointment from the Philadelphia gas department as chief weightmaster.

He won in the Democratic wave election in Wisconsin in 1890, assisted by backlash against the passage of the anti-immigrant Bennett Law in the previous session.