This was the era just before TV, when radio shows were HUGE, and American families sat around their radios in the evenings, listening to their favorite entertainers, and no entertainer of that era was bigger than Kate Smith.
Kate was also very patriotic. It hurt her to see Americans so depressed and afraid of what the next day would bring. She had hope for America, and faith in her fellow Americans. She wanted to do something to cheer them up, so she went to the famous American song-writer, Irving Berlin (also wrote "White Christmas") and asked him to write a song that would make Americans feel good again about their country.
This video starts out with Kate Smith coming into the radio studio with the orchestra and an audience. She introduces the new song for the very first time, and starts singing. After the first couple verses, with her voice in the background still singing, scenes are shown from the 1940 movie, "You're In The Army Now." At the 4:20 mark of the video you see a young actor in the movie, sitting in an office, reading a paper; it's Ronald Reagan.
To this day, God Bless America stirs our patriotic feelings and pride in our country. Back in 1940, when Kate Smith went looking for a song to raise the spirits of her fellow Americans, I doubt she realized just how successful the results would be for her fellow Americans during those years of hardship and worry, and for many generations of Americans to follow. Now that you know the story of the song, I hope you will enjoy it and treasure it even more.