Hamilton, 32, played in 173 games for the Giants, tying him with Harry Carson for sixth on the franchise's all-time list, and had 157 starts.
He is credited with 526 tackles, including 376 solo tackles, and his 63 sacks places him fourth on the team's career list since sacks became an official statistic in 1982.
"Keith Hamilton was a throwback football player," General Manager Ernie Accorsi said. "He could have played in the '50s with the Gino Marchettis, the Len Fords, the Big Daddy Lipscombs and the Andy Robestellis, or in the 60's with Joe Greene, Deacon Jones and Alan Page."
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