He was selected by the New York Giants in the seventh round of the 2007 NFL draft and was also a member of the Detroit Lions.

In 2006, started all 10 games in which he played at strong safety, he earned All-Pac-10 2nd-team honors and finished 5th on the team with 47 tackles (35 solo), including 1 stop for a 7-yard loss.

[2] Johnson joined Aaron Ross, Steve Smith, Jay Alford, Zak DeOssie, Kevin Boss, Adam Koets, and Ahmad Bradshaw as 2007 Giants draft choices who contributed in their rookie season for the Giants Super Bowl XLII win.

In the NFC Championship that season against the Green Bay Packers, Johnson made a critically important play late in the 4th quarter: Fellow Giant R. W. McQuarters fumbled a punt return, and as Packer Jarrett Bush wrapped his hands around the ball to recover it, Johnson dove in and punched the ball out of Bush's hands.

The fumble was eventually recovered by fellow Giant Domenik Hixon, and they went on to win the game in overtime.