Davis stated his delight to be extending his stay in the orange and charcoal.
"It's great to re-sign and ensure I'll finish my career at a club I'm so proud to have helped build," Davis said.
"We're at a really exciting time in our club's evolution and I'm committed to being a part of that.
"I'm looking forward to pre-season and helping us have a great year in 2022."
GWS General Manager of Football Jason McCartney expressed his pleasure at being able to retain the 31-year-old for a further season.
"Phil's been an important part of our club from the very beginning so to continue his career with us into an 11th season is really exciting," McCartney said.
"He continues to be part of our leadership group and play an important role on and off the field."
Injuries hampered the key defender's 2021 campaign, missing a large portion of this season's midriff between Rounds 3 and 14.