Ryan was accompanied by his wife, Sarah, parents Bernice and Mike, as well as former Eagles coach Tom O'Brien. Former Eagles defensive lineman Mike Ruth was also present for the ceremony.
"It's great to be back here today," Ryan said to the crowd. "I've got so many unbelievable memories of playing on this field in front of so many familiar faces."
"I'm really honored to have my jersey hanging up there and very proud."
The 31-year-old native of Exton, Pa., played for the Eagles from 2004 to 2007, compiling 9,313 passing yards (807 for 1,347) and 56 touchdown passes in 43 games.
Ryan ranks third all-time in school history in passing yards and touchdown passes behind Doug Flutie (10,759 and 70) and Glenn Foley (10,039 and 72).
As a senior in 2007, Ryan set school single-season records in passing yards (4,507) and touchdowns (31). He led the Eagles to an 8-0 start and a No. 2 national ranking before finishing 11-3.
Ryan won the ACC Player of the Year award, the Johnny Unitas Golden Arm Award and the Manning Award that season while guiding Boston College to its first-ever ACC Championship Game.
Ryan finished seventh in Heisman Trophy voting in 2007. He was selected third overall by the Falcons in the 2008 NFL Draft, the highest-ever selection for an Eagles player in any sport.
In nine NFL seasons, Ryan has earned three Pro Bowl selections and holds the Falcons' all-time records for passing yards (36,004) and touchdown passes (226), among other categories.
This season, Ryan ranks second in the NFL in passing yards (3,247) and touchdown passes (24) in 10 games. Atlanta is 6-4 and sits atop the NFC South.
Boston College carried a 10-0 lead into halftime.