The 3-4 defense was originally developed by Bud Wilkinson at the University of Oklahoma in the 1940s. Chuck Fairbanks learned the defense from Wilkinson and is credited with importing it to the NFL.
Fairbanks' schemes have influenced many important winning coaches in the years following his retirement, among them Bill Parcells, Bill Cowher, and Bill Belichick.
The 3-4 defense is a defensive alignment that consists of three down linemen, four linebackers, and four defensive backs.
The defensive line is made up of a nose tackle and two defensive ends. Linemen in 3-4 schemes tend to be larger than their 4-3 counterparts to take up more space and guard more territory along the defensive front.
The nose tackle and the inside linebackers - those are three guys that are very important. But when you go through it, the nose tackle is probably the single-most important guy.
Ideally, 3-4 DEs should weigh 285–300 pounds and be able to beat double teams by getting a push. The ideal nose tackle has to be much bigger than 4-3 DTs, weighing around 330 pounds or more.
The 3-4 nose tackle is considered the most physically demanding position in football. The 3-4 almost always rushes the offense with four guys. Usually the fourth will be a linebacker.
The 3-4 linebackers must be very athletic and strong. In most cases, 3-4 OLBs lead their teams in quarterback sacks.
The corners will generally line up three to five yards off the line of scrimmage, generally trying to jam the receivers.
The free safety is responsible for reading the offensive plays and covering deep passes. He must be a quick and smart player, capable of making tackles efficiently, as well as reading the play and alerting his team of game situations.
The strong safety is usually close to the line of scrimmage. He is often a crucial part of the run defense, but is also especially responsible against passes to the tight-ends.
That is the basics of the 3-4 defense. I went through and picked out the best players who I thought would be a perfect fit for the all-time 3-4 defensive team.
Please note, these picks have been decided on players who have played at least three or more years in the 3-4 defensive scheme.