His hiring was confirmed Saturday in an announcement during the inter-league major league baseball contest between the New York Mets and Yankees at Shea Stadium.
It was announced originally Tuesday.
"It's been a long time since I've been a rookie," Strahan recently told New York Sportswatch columnist Neil Best. "I think I remember what to do."
Strahan retired June 21 after a 15-year playing career with the Giants.
He ended with 854 career tackles, four interceptions, 21 forced fumbles and two career touchdowns in a franchise-record 216 games and established the league's single-season sack record with 22 1/2 in 2001.
The Giants' second pick in the 1993 NFL draft out of Texas Southern was the third potential Hall of Famer to retire following the 2007 season, joining Green Bay quarterback Brett Favre and Oakland defensive tackle Warren Sapp.