1921 was the year of the first sports broadcast on the radio. It was on the Philadelphia Phillies game.
1936 was the first year that the Olympic Games were shown on television. This broadcast in Berlin and Potsdam was seen by over 162,000 viewers.
Feb. 4, 1937 was the first time that sports commentary was heard on TV. They first commented on amateur boxing.
1939 was the first year that an NFL game was televised. The first game was between the Brooklyn Dodgers and Philadelphia Eagles to approximately 500 TV set owners.
May 16, 1960 was the first night a major league baseball game was on TV in color.
Sept. 1979 was when the first all-sports network (ESPN) aired.
Television Sports Production
Olympic Broadcasting Services
The History of Sports Television Broadcasting