The first recommendation was to change the words 'my flag' to 'the flag of the United States'. A year later, they added 'of America'. It wasn't adopted as the national pledge by congress until December 28, 1945.
In 1954, President Eisenhower signed a bill to add the words "under God" just after "one nation". Eisenhower had recommended the change to congress after hearing a sermon in a Presbyterian church.
Rev. Dr. George Docherty is the one who had delivered the sermon, and was even quoted when congressman Charles Oakman spoke to the house, urging them to pass the bill. He even ended his speech with, "Mr. Speaker, I think Mr. Docherty hit the nail square on the head."