The $48 million deal includes $26 million fully guaranteed, a source told ESPN's Adam Schefter.
The Baltimore Ravens sent Jernigan and a 2017 third-round pick to the Eagles on April 4 in exchange for Philly's third-round pick, which was higher in the round.
"Since the day he entered the building, Tim has been a difference maker both on the field and around the building," the Eagles said in a statement. "He's a tough, physical and relentless player who brings energy and enthusiasm every day. Tim possesses a lot of the qualities that we look for as we continue to build this team and we are excited about his future here in Philadelphia."
Jernigan, a 25-year-old Florida State product, has thrived in defensive coordinator Jim Schwartz's attack scheme. Jernigan has a team-high eight tackles for loss, 1.5 sacks and five hurries on the season.
Paired with Fletcher Cox, he is part of one of the best defensive tackle combinations in football. It is also now among the richest. In 2016, the Eagles signed Cox to a six-year deal worth over $100 million, with over $36 million fully guaranteed. More than $62 million in guarantees is now earmarked for two players on the interior of the defensive line.
Overall, Jernigan, a second-round pick in 2014, has 14.5 sacks and one interception in four seasons.