Danning first played with the New York Giants in 1933. From 1934 to 1936, he served as the Giants reserve catcher, working behind Gus Mancuso. 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. However, they were allowed to stay when Giants manager Bill Terry threatened he would take the whole team to another hotel if his Jewish ballplayers were not allowed in.