A solitary goal from Antoni Sarcevic's saw the Cod Army triumph at the home of football with a 1-0 win over Burton Albion.
Morris, who has been on loan at Town since February, played the full match in what was a tight and nervy affair. His 17th and final appearance for the club.
Fleetwood started both halves strongly, but there was little between the two sides until Sarcevic's 75th minute free-kick flew into the back of the net.
Victory means Graham Alexander's side have now won promotion in six of the last 10 seasons.