Johnson is coming off a spectacular season in which he caught 96 passes for a league-best 1,681 yards and 16 touchdowns. He became the third player in NFL history with at least 95 receptions, 1,600 yards and 15 touchdowns in a season, joining Jerry Rice and Randy Moss.
He's also one of six receivers to post at least 45 TD catches and 5,000 yards receiving in a four-season span, along with Rice, Moss, Terrell Owens, Marvin Harrison and Lance Alworth.
"There are not many guys when you do a contract of this magnitude," team president Tom Lewand said. "We obviously did one years ago with Barry Sanders, and he was one of those kinds of guys, who is so special on the field, truly deserving of a contract of this size, and a guy who you have no doubt will handle all that comes with it with a great deal of skill on and off the field."
Stafford is coming off his first full season of good health. Johnson and the rest of the team benefited.