The 27-year-old was due to come out of contract at the end of next year, but is now committed to the Hawks until the end of 2029.
Reeves played a career-best 21 games in 2023 but has managed just five senior appearances over the past two seasons, with Lloyd Meek emerging as coach Sam Mitchell's No.1 ruck choice.
But the AFL's decision to remove the substitute rule - allowing teams to have five interchange players on the bench - could open up opportunities as clubs consider picking two genuine ruckmen.
Hawthorn list manager Mark McKenzie was delighted Reeves had re-signed with the club.
"Ned has always been a crucial part of what we're building towards and we are delighted to lock him away for a further three years," McKenzie said in a statement.
"With a strong body of work already under his belt at AFL, Ned has shown his capacity to compete with some of the league's best rucks.
"At 27 years of age, Ned is reaching the peak of his powers and we are confident his best footy is ahead of him in the next few years."
While Reeves' decision is a boost for Hawthorn, their list management priority lies with convincing young gun Josh Weddle to sign a new deal.
Weddle is out of contract at the end of 2026 and has already attracted a huge offer from Essendon, reportedly worth about $10 million over seven years.
The 21-year-old has played 60 games in three seasons with the Hawks and will wait until the new year before giving serious consideration to his playing future.
Essendon's offer to Weddle came after Hawthorn ruffled feathers with a bold play for Bombers star Zach Merrett.
The Hawks couldn't convince Essendon to trade their then-captain, who has since returned to the Bombers and given up his leadership role.