Bud Wilkinson originally devised the 3-4 defense in the late 1940s. He was head coach back then of the Oklahoma Sooners when they won three national championships and 14 conference titles.
In the early 1970s, Bill Arnsparger developed the 3-4 defense when he was head coach of the Miami Dolphins. He helped popularize the scheme by being successful in using it.
Chuck Fairbanks introduced the 3-4 defense to the NFL. During his second season as head coach of the New England Patriots in the year 1974, he used the 3-4 defense on almost every down. In fact, he used the scheme as his team's base defense. He learned the 3-4 defense when he was in college and used it when he became head coach of Oklahoma.
Another big name in football who bought the 3-4 defense to the NFL would be Bum Phillips. He used the 3-4 defense a lot when he was still the defensive coordinator of the Houston Oilers. That was before he got the position as head coaching job of the team.
The late Hank Stram, who was in the Pro Footbal Hall of Fame, used the 3-4 defense to win a championship 40 years ago. But then, just like all others, he never stuck with the scheme.
Another pioneer of the 3-4 defense would be Joe Collier. He was the first one to use the 3-4 defense in the pros during his time as defensive coordinator of the Buffalo Bills. That's 45 years ago. But despite he was considered a pioneer, he still did not use the 3-4 defense that much.
The 3-4 defense has a lot of versions, each of them created by different people. Therefore, this scheme has different styles, as different as the personalities of the people who've created it.
To sight an example, Dick LeBeau was the Defensive Coordinator of the Steelers. He was star defensive back at Ohio State and was a draft choice of the Browns in 1959. He's the kind that wants action and created the 3-4 defense attacks that all the time from all angles and directions. That kind of style forces single coverage all over the field which leaves a great risk to his units if all rushers are picked up. But he still takes the risk. This was a totally different 3-4 defense than what Rutigliano used in 1980.
In the late 1980's, the New York Giants won two Super Bowls making them one of the top teams in the NFL. The reason behind their success was the brutal 3-4 defense. They had two HOF linebackers in Harry Carson and Lawrence Taylor. Bill Belichick was the defensive coordinator. It was said that he used the success of the Giants to catapult himself as head coach for the Browns in 1991.
In the previous year, the 3-4 defense wave the Browns a record of 462 points, including 58 in one game alone. After all, if it was not for the genius of the 3-4 defense, Belichick would have never gotten the Cleveland job.
The 3-4 defense is the alignment used by Romeo Crennel for his four seasons as Browns coach. It was also the same alignment that helped Belichick, Crennel, and Mangini win three Superbowls earlier this decade with the Patriots.
The football history has come a long way, then, it's hard to follow and keep track of its path. The men that are mentioned here are considered big names in American Football. Bill Arnsparger, Chuck Fairbanks, Dick LeBeaus, Bill Belichick, they all contributed to the popularity of the 3-4 scheme. They made revisions as well. But even though the 3-4 denfense went through a lot of changes, it is still considered one of the best defenses in football today.