The Santa Tracker tradition started way back in 1958 when NORAD was still Continental Air Defense Command (CONAD). Here’s NORAD’s introduction to the Santa Tracker tradition:

For more than 50 years, NORAD and its predecessor, the Continental Air Defense Command (CONAD) have tracked Santa. The tradition began after a Colorado Springs-based Sears Roebuck & Co. store advertisement for children to call Santa on a special “hotline” included an inadvertently misprinted telephone number. Instead of Santa, the phone number put kids through to the CONAD Commander-in-Chief’s operations “hotline.” The Director of Operations, Colonel Harry Shoup, received the first “Santa” call on Christmas Eve 1955. Realizing what had happened, Colonel Shoup had his staff check radar data to see if there was any indication of Santa making his way south from the North Pole. Indeed there were signs of Santa and children who called were given an update on Santa’s position. Thus, the tradition was born.