After Harvard, Miles returned home to Grand Rapids in 1991 and joined Varnum Riddering Schmidt & Howlett, a 150-attorney law firm, as an associate. He specialized in business law and cable/telecommunications law. Miles made partner in 1997 at the age of 29—the first person of color to become a partner in the firm's 110-year history and the first African American male to become a partner at a Grand Rapids law firm with more than 10 attorneys. Miles served an elected term on the Varnum management/policy committee from January 1, 2002, to December 31, 2004. In 2006 he joined the national law firm of
Dickinson Wright as a partner based in Grand Rapids.
The Grand Rapids Business Journal named Miles to its 40 under 40 business leaders list in October 1998, December 2002, and November 2007.
Business Direct Weekly named him to its 40 business leaders under 40 in March 2004. In 1999, the Grand Rapids Press named Pat Miles one of 10 corporate leaders to watch in the new millennium. As U.S. Attorney Miles supported improving law enforcement and community relations in the cities of Battle Creek, Benton Harbor, Grand Rapids, Holland, Kalamazoo, Lansing, and Muskegon. He also initiated several programs, including violent crime prevention coordination in several cities, a program to reduce recidivism by assisting returning citizens in finding employment and social services, and a program for middle school students called "Justice Scholars" to learn about the legal system. In addition, his office obtained the first federal sex trafficking conviction in Western Michigan and led efforts to fight the opioid epidemic. He oversaw the federal investigation and child pornography case of sex offender Larry Nassar that led to Nassar's federal criminal conviction in 2017. Miles announced his resignation as United States Attorney for the Western District of Michigan on January 5, 2017, which took effect on January 20, 2017. On May 1, 2017, Miles joined
Barnes & Thornburg LLP in Grand Rapids. Miles focuses his practice on business counseling and transactions, white collar cases, internal investigations, corporate compliance, and monitorships. In May 2023 Miles was a commencement speaker for
Saginaw Valley State University and awarded an Honorary Doctor of Humanities degree. ==Campaigns==