Hired by the Cleveland Indians in 1903, he served that club as traveling secretary (1903–08), vice president and de facto general manager (1908–16, 1918–22), and president (1922–27). During this time he often acted as a mediator between AL president Ban Johnson and Commissioner Kenesaw Mountain Landis. He served under the Indians first owner, Charles Somers, and under their second, Jim Dunn. Dunn had initially fired Barnard upon taking over in 1917. Realizing he'd made a mistake, Dunn brought Barnard back to the team in 1918. Barnard stayed on as president after Dunn's death in 1922, running the team for Dunn's widow and estate.
When AL owners removed Ban Johnson, the league's founder, from the league presidency in 1927, Barnard, after first clearing the way by arranging the sale of the Indians to a group headed by Alva Bradley, replaced him. He was re-elected to a 3-year term on December 9, 1930, but died suddenly 3 months later just prior to an examination at the Mayo Clinic in Rochester, Minnesota. Coincidentally, Johnson died just hours later.