The deal tops off a special week for Hayward, who will make his Swans debut against the Western Bulldogs at Etihad Stadium on Friday night.
Hayward was taken with the 21st overall pick in the 2016 AFL National Draft, and appeared in two JLT Community Series matches over the pre-season competition.
Swans Head of Football Tom Harley says the club was excited with Hayward’s decision to re-commit so early in his career.
“We’re very happy that Will has decided to extend his first contract with the Club by a further year,” Harley said.
“Will’s made an immediate impression with his willingness to learn and also his thirst for the contest.
“It’s exciting for us to have Will commit and play his first game all in the same week, and we look forward to watching his progress.”