Tannehill was born in Dayton, Kentucky. He broke into the National League at the age of 19 with the Cincinnati Reds; however, he struggled in 29 innings and did not reappear in the major leagues until three years later. After a partial season with the Pittsburgh Pirates in 1897, Tannehill set a career high in both innings pitched (326+2⁄3) and wins (25) in 1898. Tannehill had several good years with the Pirates until his career year in 1901, when he led the National League in ERA at 2.18. Tannehill posted an even better ERA in 1902 at 1.95, but as the league ERA had dropped even more precipitously, he did not lead the National League in ERA.
After six years with the Pirates of the National League, Tannehill got involved in a salary dispute with Pirates owner Barney Dreyfuss. As a result, Tannehill jumped to the startup American League franchise the New York Highlanders. After the season, he was traded by the Highlanders to the Boston Americans for Tom L. Hughes. Tannehill still had some good years left, however; he was an important part of the Boston Americans championship team of 1904. Tannehill pitched a no-hitter against the Chicago White Sox on August 17, 1904 (his brother Lee went 0-for-3 for Chicago) and continued to be an above average pitcher until 1907. After this however, Tannehill went into precipitous decline, as he was traded to the Washington Senators for Case Patten. Tannehill retired from baseball in 1911, with a career ERA of 2.79 and 197 career wins.
In his last years, Tannehill worked in a Cincinnati machine shop and was a frequent visitor to Crosley Field, the home of the Cincinnati Reds from 1912 to 1970. He suffered a stroke on September 16, 1956 at his home in Dayton, Kentucky and died six days later at the age of 82 at Speers Hospital.[1][2]