Whether Kling was born Jewish is a matter of dispute, but his wife was, and they were married by a Kansas City Rabbi Harry H. Mayer, of Temple B'nai Jehudah, a Reform congregation.

For what was left of the season, he caught fifteen games and had a batting average of .294[5] He also acquired the nickname "Noisy John", because he kept up a constant chatter on the field; some baseball historians have noted this was part of his skill in waging "psychological warfare" on his opponents.

[2] By all accounts he was an exceptional defensive catcher, praised for his skill in throwing out runners who were caught stealing.

He was also a reliable hitter, and a pivotal member of the team that became known as the Chicago Cubs, an integral part of the dynasty, which included Hall of Fame infielders Joe Tinker, Johnny Evers and Frank Chance.

[6] Overall, he played in 1,261 major league games, batting .272 with 20 home runs and 514 RBIs in his major-league career.

[15] During that time he continued to compete in pool, winning the world billiards championship, and played semi-pro baseball with a Kansas City team.

He sat out the entire 1909 season, and in early October competed against Charles "Cowboy" Weston and won the world's championship of pool.

[16] When he decided to come back to baseball in early 1910 and asked to be reinstated, a debate ensued as to whether he should be permitted to return since he had not honored his contract during the 1909 season.

[19] And despite his often-divided loyalties, baseball writers agreed that Kling was among the best players of his era; in fact, his obituary described him as "one of the greatest catchers the Chicago Cubs ever had".

[20] After a decade of success with the Cubs, Kling was traded to the lowly Boston Braves, where he spent the 1911 and 1912 seasons.

[23][24] In 1933, he purchased the Kansas City Blues of the American Association and was able to generate more interest in the team and increase their attendance within a year of taking over.

In late January 1947, while returning from Miami to Kansas City, he suffered either a heart attack or a cerebral hemorrhage and died in the hospital at age 71.