Coaching the 4-3 Defense: The Basics

4-3 Defense Run FitsThe 4-3 Defense has been one of the most successful defenses over a long period of time in the history of football. Teams have won with the 4-3 Defense at every level, from Youth Football to High School, College and the NFL. In its current form, it has survived over 30 years of change on the Offense side. No defense has managed to adapt to the changing environment of the game like the 4-3 Defense.

The 4-3 Defense began in the 1960s, but grew to prominence in the 1980s, starting with the University of Miami. Known today as the Miami 4-3, or the 4-3 Over Front, the defense the Hurricanes developed was initially intended to stop the University of Oklahoma’s Wishbone Option. Not only was it successful there, but the defense was adaptable to much more.

So what is the 4-3 Defense, why has it been so successful, and how can you install it on your team this season?

What Makes a 4-3 Defense

The name of the game today, particularly against the hottest Spread Offenses in the country, is speed. Speed kills, you can’t teach speed, and there’s no substitute for speed. You either got it, or you don’t.

The 4-3 Defense allows you to put more fast players on the field. Many people mistakenly believe you need four true Defensive Linemen to run the 4-3 Defense. The truth is, you can play the 4-3 Defense with only two Defensive Linemen, or even just one true defensive lineman. Players that would normally be Linebackers in other defenses are perfectly suited to play the Defensive End positions in the 4-3.

Option to the weak side against a 4-3 Over Front

Most coaches will look for Safeties to play the Outside Linebacker positions, and get faster bodies at every position on the field. Bigger, slower defensive linemen are asked to play the Offensive Line on teams that run the 4-3 Defense.

Besides being all about speed, the 4-3 Defense is also a Spill Defense. That means that you are always trying to force the ball carriers to run East and West, not North and South. As long as they are forced to run sideways, your speedy defenders have a chance to run them down and gang tackle them for minimal gains.

The 4-3 Defense is a 7 Man Front, which means there are four players in the secondary (2 Safeties and 2 Corners), which gives you more flexibility in your coverage packages. It also allows for a great deal of creativity in your blitz package.

The drawback of a 7 Man Front, compared to the 8 Man Fronts of the 4-2-5 Defense or the 3-5-3 Defense, is that at least one player has to be a 2-Gap Player. This means that some players do not know what area they will be responsible for defending until they read the keys the Offense gives them. While the 3-4 Defense will commonly 2-gap the Defensive Linemen, we 2-gap the Linebackers in the 4-3 Defense (particularly the Mike Linebacker) .

Base Alignment of the 4-3 Defense

The alignment of the 4-3 Defense is what allows you to maximize speed on the field, while not sacrificing run defense. Putting the right players in the right place is important to the success of the defense.

Strong Tackle: Aligns in a 3-technique, outside shade of the Guard on the strong side. He is your best Defensive Lineman, and must be able to command a double team from the Offensive Line.

Nose Guard (or Weak Tackle): Aligns in a 1-technique, a weak shade on the Center. Your second best Defensive Lineman or a wrestler-type player if he’s smaller. Quick and able to cause problems up front.

Strong End: Bigger and stronger of the two Defensive Ends, he aligns in a 9-Technique on a Tight End (outside shade) or a 5-Technique if there is no Tight End on the strong side. The Ends are tilted at 45 degree angles to help spill the football.

Weak End: Faster, more athletic of the Defensive Ends. If you have one guy that is incredibly athletic but doesn’t really learn the playbook too well, put him here. He can be completely cut loose to wreck shop.

Mike Linebacker: Your one true linebacker. He stacks behind the Nose Guard in a Weak 10. A tackling machine between the Tackles, but he does not have to play sideline to sideline (it’s a bonus if he can). He is a 2-gap player and the leader of the defense in most situations. The Mike will take a pounding against 2 back teams, so you need someone with enough size to handle the punishment.

4-3 Defense Quarters vs Curl-Flat RouteSam Linebacker: Depends on what you’re seeing, the Sam is either your most athletic Linebacker, or your 2nd biggest Linebacker. The Sam aligns over the C Gap, in a strong 50 (outside shade of the Tackle, 5 yards off the ball). If you see a lot of 2-back running game, he needs to be bigger because he’ll be taking on the run (particularly Power/Counter runs). If you see a lot of 1-back, no TE spread, your Sam will be walked out of the box most of the time (unless you are rolling down a safety).

Will Linebacker: Normally the more athletic of the 3 Linebackers, a hybrid safety type of player. He does not have to take on the Iso block of a Fullback, because the Mike does it. But he is dealing with less space and more help than the Sam Linebacker is. The Will aligns in a loose 50, 5 yards off the ball with his inside foot even with the outside foot of the Defensive End.

Free Safety and Strong Safety: Depending on your coverage, you will have to decide what you need from these guys. We like a base Quarters coverage, where the Safeties are the contain players against run teams. Because of that, they need to be two of our best athletes and top tacklers.

Cornerbacks: In our Quarters Coverage, the Corners can be average athletes as long as they are smart enough to play their match-ups. If you decide to run a Cover 2 Defense, as the Miami Hurricanes initially did when they installed the 4-3 Defense, you will need bigger and more athletic Corners.

What you choose for coverage will dictate a lot about how you choose personnel for your secondary. Always remember that your front and your coverage have to match-up, and your contain players are determined by your coverage. Your Defensive Line and your Mike Linebacker will always be spilling the football to the outside. Make sure they are spilling to someone, and someone who is capable of making a play.

Coaching the Attacking Defensive Line

Your Defensive Line in the 4-3 Defense will be on the attack. They are expected to make tackles, just like the Linebackers are. But they first have to take control of the Line of Scrimmage.

We teach our Defensive Linemen to align on the outside shade of their Offensive Lineman, and attack his outside half. The inside hand strikes the breast plate, while the outside hand controls the shoulder pad – framing the arm pit with their hands.

You want to keep things simple for the Defensive Linemen, because they cannot see much of what is going on and they are in a brutal battle on every snap. Our Defensive Linemen are taught to react to three blocks: 1) Block To; 2) Block Away; 3) Pass Block.

  • Block To: Never allow the Offensive Lineman to reach you or to drive you. Attack and strike, drive your hips into your gap responsibility. Extend your hands, pull down with the outside hand and rip through the blocker with the inside hand to get even with the blocker’s hip. Once you establish control, you are free to pursue to the football.
  • Block Away: If the Offensive Lineman in front of you does not block you, expect someone else to. Block Down, Step Down is the principal rule of the 4-3 Defense. If your blocker blocks away, squeeze down to replace where he left. Treat this as run away and close fast, looking to wrong arm the next blocker (pulling guard or fullback).
  • Pass Set: Get into a pass rush mode. Maintain your pass rush lane integrity.

Remember that we want to use faster, more athletic Defensive Linemen than you may be used to seeing. We don’t want them staying engaged with the Offensive Line for long. They are just as capable of running down a play as the Linebackers are – after all, if you’re doing it right, they probably used to be Linebackers!

Preparing Your Linebackers to Be the Heart of the Defense

Even with our more athletic Defensive Linemen, the heart of any defense will always be the Linebackers. They are the only players who are heavily responsible for both defending the run, and covering the pass. In the 4-3 Defense, they require plenty of attention because they are your 2-gap defenders.

Cover 6 for 4-3 Defense vs TwinsIn particular, the Mike Linebacker is going to be a 2-gap player. He keys on the nearest back (the fullback in 2-back sets, or the single back in 1-back sets). Based on the reads he gets, he is defending to the flow side. If he gets flow strong, he is responsible for A Gap Strong. On flow weak, he is responsible for B Gap Weak.

The Mike Linebacker is always a spill player. He is going to be in a physical battle with the fullback all night against power running teams. You need a player who is mentally and physically up to the challenge to play this position.

The Sam Linebacker is responsible for C Gap strong on runs to his side. Where this is going to be important is when you play teams that run a lot of Power and Counter. He will be involved in a gap exchange with the Defensive End, who steps down to replace a down blocking Tight End, and wrong arms the kick out blocker. The Sam should fill tight off his hip to make the tackle on the spill.

When there is no Tight End, the Sam walks out to split the difference between the Offensive Tackle and the #2 Receiver. Against Trips formations, he splits the difference between the #2 and #3 Receivers.

The Will Linebacker will never have to take on a direct rushing attack, because of the 2-gap qualities of the Mike Linebacker. On run to his side, he uses a spin down technique. He shuffles down behind the Defensive End and looks for daylight inside. If the Mike Linebacker has filled all of the daylight inside, the Will slides to the outside waiting for the back to spill. However, if there is any daylight inside, the Will must fill it along with the Mike Backer.

Coverage and the Secondary

The role of the Safeties and Corners will be completely determined by the coverage you choose. Their alignment, personnel characteristics, and more cannot be discussed without establishing the coverage. Some teams prefer to use a Roll Cover 3, while others prefer to use Quarters Coverage.

To see what we do with our coverage behind the 4-3 Defense, take a look at this video on Quarters Coverage.

Further Reading on the 4-3 Defense

Want to become an expert in the 4-3 Defense? Ready to start installing it with your own football team? We have a ton of resources here to help you out.

What to see how we blitz in the 4-3 Defense? Check out some of these Zone Blitzes, or read Dominating Football Defense with the Zone Blitz eBook.

Get a complete Install of the Miami 4-3 Defense with Coaching Football’s 4-3 Over Defensive Front eBook.

And if you’re ALL IN on the 4-3 Defense, you need to take it to the next level with The 4-3 Defense eCourse at

There are tons of articles on coverage, blitzes, and more on the 4-3 Defense including reads, keys, drills and techniques for each position within the Membership Section of You can get a 7 Day Free Trial and cruise around to look at it all. Click Here to Get Started!

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  • Coach Daniel

    I like playing the 6 with the DE but I think it takes time to teach. If it’s something you are already teaching, it’s a great adjustment. We found it was easier to have the weak DE move into a 7, straighten up his stance (they are normally tilted), and just attack the inside shoulder. It’s not beautiful, but it keeps him from getting down blocked. Our weak DE is not the biggest guy on the field.

  • Tommy Acklin

    When we get 2 TE, our weak side DE will align in a 6 and still be responsible for C gap. The Shelled Secondary will keep all of your run fits in tact. If the the TE goes vertical his is bracketed by the Corner and Safety. If the TE Blocks, the Corner and Safety Identify their run fits. The 2TE set becomes a much bigger issue when a shelled Secondary is not used, because you have a FS over the ball.

  • Mike Hause

    I have been a coach for over 30 years and love the 43 defense. But one problem still keeps coming up. What happens when you get 2 TE’s. You can’t play the weak DT on a 0 shade unless you adjust the secondary or linebackers. I have tried many things but would like other suggestions.