March 5 is the deadline for the Bills to apply the franchise tag on Johnson, but the two sides preferred to work out a long-term deal instead.
Financial terms of the deal were not disclosed in either announcement.
The signing of Johnson is a key step in the Bills desire to keep their current core group of young players together. When the 2011 offseason began, the Bills lost starting linebacker Paul Posluszny to the Jacksonville Jaguars, even though Posluszny had said he wanted to stay in Buffalo.
The signing of Johnson likely means that he and Ryan Fitzpatrick, who signed a seven-year contract during the 2011 season, will be working together for quite a few years. That duo has clicked well enough together that Johnson had two consecutive, 1,000-plus receiving yard seasons—a feat not other player in Bills' franchise history had ever accomplished before.
With Johnson under contract, the Bills will focus their attention on their other key free-agents before the start of free agency. Other Bills free-agents of note include tight end Scott Chandler, safety Bryan Scott and restricted free-agents Kraig Urbik and Chad Rinehart.
The Bills can begin targeting pass-rushing free-agents as well, especially those that didn't receive a franchise tag by today's deadline.