According to USFlag.org, President Harry Truman signed an act of Congress to officially designate June 14th as National Flag in the USA. Another informative website, military.com, cites that in "1916, the anniversary of the Flag Resolution of 1777 became a nationally observed event by a proclamation by President Woodrow Wilson," and that is was "designated as National Flag Day," on "August 3rd, 1949, when an Act of Congress designated June 14th of each year as National Flag Day." Note that, was the 33rd President of the United States from 1945–1953.
To honor the flag of the USA today, affectionately known as Old Glory, parades will be held across the nation along with events sponsored by Veteran's groups. If you have a flag on a lapel or a place to display one today, give pause to remember the significance and perhaps review some information on the ushistory.org website, where flag news, regulations and information is readily available!
To your success, however it is measured.