[5] Robert's love of baseball inspired both Harry and his older brother Ike Danning, who played for the St. Louis Browns in 1928.

[5] When the Bridgeport franchise folded, mid-season 1932, Danning moved to Winston-Salem, North Carolina to be part of the Piedmont League.

In 1934 in spring training, despite a team reservation Jewish ballplayers Phil Weintraub and Danning were refused entry to the Flamingo Hotel in Miami Beach, Florida, which had a "No Jews" policy.

[1] In the 1937 series, CBS announcer Ted Husing nicknamed Danning "Harry The Horse" for Damon Runyon's Broadway character.

[18] Through 2010, he was ninth all-time in career hits (behind Al Rosen) among Jewish major league baseball players.

[1] He had a career fielding percentage of .985,[1] leading National League catchers three times in putouts, and twice in assists and baserunners caught stealing.

[20] He caught the screwballer Carl Hubbell, and was also a teammate of Mel Ott, Bill Terry and Travis Jackson, four Hall of Famers.

During World War II, Danning served in the United States Army, and announced his retirement from baseball after his military service.