John Tener was born in County Tyrone, Ireland to George Evans Tener and Susan Wallis. In 1872, Tener’s father died and the family moved the following year to Pittsburgh, Pennsylvania. Tener attended public schools and later worked as a clerk for hardware manufacturer Oliver Iron and Steel Corporation from 1881–1885. In 1885, Tener, who was six-foot-four (1.93 meters), decided to try his hand at professional baseball. He joined the Haverhill, Massachusetts minor league baseball team in the New England League as a pitcher and outfielder and was a teammate of future Hall of Fame players Wilbert Robinson and Tommy McCarthy. Later that year, Tener made his Major League debut with the Baltimore Orioles of the American Association, playing in a single game as an outfielder. While playing in Haverhill, John Tener met his future wife, Harriet Day. They married in October 1889. After his brief appearance in Baltimore, Tener continued playing minor league ball, but also returned to the corporate world, working for the Chartiers Valley Gas Company in Pittsburgh and Chambers and McKee Glass Company. In 1888, Cap Anson, the manager of the Chicago White Stockings (now the Chicago Cubs), noticed him pitching in Pittsburgh and signed Tener to a contract. John Tener was a pitcher and an outfielder for two years in Chicago with moderate success. He notched a 7–5 record with a 2.74 ERA in 1888 and went 15–15 with a 3.64 ERA in 1889.

After the 1888 season, John Tener accompanied the team on a world tour of Australia, New Zealand, Egypt, France, Italy and England. While in England, Tener was chosen to help explain the game of baseball to the Prince of Wales, who would go on to become King Edward VII. Tener was elected as Secretary of the Brotherhood of Professional Players, an early players union and served under President John Montgomery Ward, a future member of the Baseball Hall of Fame. In 1890, unhappy with baseball’s reserve clause, Tener joined other players in jumping to the Players’ League. Playing for the Pittsburgh Burghers, Tener compiled a poor 3–11 record. The league folded after one year and Tener decided to retire from prefessional baseball. He entered the banking business in Charleroi, Pennsylvania in 1891, becoming a cashier at the First National Bank of Charleroi. By 1897, he was the president of the bank. Over the years, Tener became a prominent business leader, founding the Charleroi Savings and Trust Company and the Mercantile Bridge Company.

After leaving baseball, John Tener returned to his business interests in Pittsburgh. In 1926, he tried to gain the Republican nomination to run again for Governor but was unsuccessful, finishing third at the convention. In the 1930s, Tener was elected as a director of the Philadelphia Phillies. In 1935, Tener’s wife Harriet died. In 1936, he married Leone Evans who died in 1937 after an illness. He engaged in the insurance business until his death, aged 82, in Pittsburgh in 1946. He was interred in Homewood Cemetery in Pittsburgh. Buildings named in his honor include a residence hall in the East Halls area of the University Park campus of the Pennsylvania State University and the Charleroi Public Library. In 1999, the Pennsylvania Historical and Museum Commission installed a historical marker in Charleroi, noting John Tener’s historic importance.