The holders made it nine titles from the last 10 tournaments with a convincing win at Old Trafford.
Samoa were the first Pacific Island team to reach the final in World Cup history after their thrilling golden-point victory over hosts England in the last four, and certainly had the backing of a packed Manchester crowd.
But after their solid start, two early tries from Latrell Mitchell and James Tedesco set firm favourites Australia on course to continue their domination of the competition.
Liam Martin’s third try of the tournament, after a sustained spell of Samoa pressure, gave the holders a 14-0 lead which they held until the break, before another converted try from Cameron Murray in the second half put Australia in total control.
To their credit, the Samoans did not give up and nearly brought the house down when Brian To’o deservedly got them on the scoresheet with a well-worked try, getting fans dreaming of a remarkable comeback.
The Kangaroos quickly dashed any such hopes with another try, a second of the game from Tedesco, before Samoa did have one more memory to take home from a memorable tournament as Stephen Crichton intercepted the ball and crossed the line.
Mitchell had the final say for the brilliant Kangaroos with another fine try in the final minute, ensuring that since 1972 Australia have only returned from one World Cup without the trophy in their hands.
Additional reporting from Reuters