He worked as a law clerk for Judge Thomas E. Fairchild on the United States Court of Appeals for the Seventh Circuit from 1982 to 1984.

[2] On September 28, 2021, The Wall Street Journal revealed in an investigation that Conley was one of more than 130 federal judges who violated U.S. law and judicial ethics by failing to recuse themselves from court cases between 2010 and 2018 involving companies in which they and/or their family held shares.

On March 10, 2017, Conley granted a request blocking President Donald Trump's administration from enforcing its newly revised travel ban against a Syrian family from the city of Aleppo, saying that daily threats against the man's wife and child could cause "irreparable harm".

A new complaint filed after the issuance of the second order maintained the revised ban still infringed upon the man's freedom of religion and right to due process.

[8] On April 2, 2020, Conley declined to postpone the 2020 Wisconsin Democratic primary despite arguments that the COVID-19 pandemic created a health risk for in-person voters.