Hargrove, 28, leaves the suddenly deep Saints depth chart on the defensive line for the Eagles, who will use him similarly, as an end and tackle.
Hargrove received a one-year contract from the Eagles.
Most notably, the Eagles have added the market's top prize, CB Nnami Asomugha, plus RB Ronnie Brown, DT Cullen Jenkins, DE Jason Babin, QB Vince Young, and others.
One of the best feel-good stories of Super Bowl XLIV, Hargrove overcame being orphaned at age 9, alcohol addiction, served long NFL suspensions and re-emerged in New Orleans as a solid contributor in a defensive line rotation. He started six games in 2009 but none in 2010, contributing six sacks, three forced fumbles and 53 tackles over the past two seasons.
Saints DE Will Smith told ESPN's Kevin Seifert before Super Bowl XLIV that Hargrove was "the heart and soul of our team."
In June, Hargrove suffered the loss of his brother, Terrance, in a violent murder in North Port, Florida.
The Saints signed DT Aubrayo Franklin yesterday and DE Turk McBride earlier this week, closing the door on Hargrove's potential return to the Saints.