“He chops trees by day and hunts The Log by night. His bottle of Rage spills everywhere when he dies.”
The Lumberjack card is unlocked from the Frozen Peak (Arena 8) or a Legendary Chest. He is a very fast, single-target, melee troop with moderate hitpoints and a high damage output. A Lumberjack card costs 4 Elixir to deploy. Upon death, he drops a bottle of Rage that increases the attack and movement speed of friendly troops and buildings in the spell's effective radius.
The Lumberjack is most effective when supported with other troops because when he dies, the Rage will increase the other troops' (in its effective radius) damage output. Thus, it is not effective to use him alone. For this strategy, place him near or at the front of a push so when he dies, many of the troops in the push will still survive and undergo the rage effect, making them much more deadly.
He can also be used defensively. If he is defeated near your Princess Tower, the resulting Rage spell will be dropped on the Arena Tower, increasing its attack speed. You can also capitalize on this by placing other buildings in front of or near the Arena Tower.
You can use the Lumberjack in combination with a Minion Horde. Place the Lumberjack first and the Minion Horde right behind. The arena tower will focus on the Lumberjack first and the Minion Horde will deal massive damage to the tower.
An Ice Golem and Fire Spirits combo is powerful enough to destroy this combo for a 5 Elixir advantage. Place the Ice Golem first to distract the Lumberjack and Minions then place the Fire Spirits to defeat the Minions and severely damage the Lumberjack.
An effective strategy is to place a tank, such as a Giant, then support it with the Lumberjack. If your opponent ignores the Lumberjack, he'll be able to take out troops or buildings attacking the tank due to his high damage. If they eliminate him, his rage will cause the tank to get in lots of additional hits. However, this strategy is very weak to swarms, so bring a cheap area damage spell like Zap or Arrows.
Even though the Lumberjack is best used in affiliation with other troops so that they can benefit from the dropped Rage, it is not wise to ignore the Lumberjack. Left alone, he can deal lots of damage to the player's tower.
Combining the Lumberjack with the Ice Spirit can leave a Crown Tower with very little health.
He has similar damage per second as the Mini P.E.K.K.A., so he is not to be ignored. Unlike the Mini P.E.K.K.A., his high hit speed can eliminate Goblins and Skeletons much more quickly so have other troops at the ready. The Lumberjack, however, is still weak to the Skeleton Army. There are just too many units for the Lumberjack to defeat fast enough.
If you place the Lumberjack near the Three Musketeers you can surprise the enemy with the sheer speed and damage, but be sure to pull out the Three Musketeers so as to surprise your enemy.
Don't deploy the Mini P.E.K.K.A directly on the Lumberjack as the Lumberjack's fast attack speed can do a lot of damage to it and even possibly take the Mini P.E.K.K.A. out.
He is also useful for protecting other glass cannons from the Valkyrie due to his high damage per second.
A Lumberjack can be used to counter a Graveyard and Poison combo. He will quickly defeat the Skeletons as they appear, and he will survive the Poison. He can clean up every single Skeleton from Graveyard with the help of the Crown Tower, as long as there's nothing tanking for the Graveyard.
If there is something tanking for the Graveyard, the Lumberjack won't be able to hit all the Skeletons fast enough. They will soon overwhelm and defeat the Lumberjack and do heavy damage to, if not completely destroy, the Crown Tower.
The Lumberjack pairs well with a Balloon. Place the Lumberjack first at the bridge, then the Balloon, forcing the opposing tower to the Lumberjack first. When he dies (he would have also done massive damage already to the Crown Tower), his Rage will increase the Balloons speed and attack speed, defeating the crown tower, so this push should not be left alone.
A Rocket can defeat this push for a positive 3 Elixir trade if the Rocket is placed at the right place at the right time.
A Minion Horde can also defend this push for a 4 elixir trade. The minions would effectively take out the Lumberjack and take out the Balloon in time before it reaches the Crown Tower.
During the Lumberjack's deploy time, he can be seen drinking his bottle of Rage.
He is the only troop that can affect allied troops' stats, through his bottle of Rage.
The Lumberjack seems responsible for creating The Log. The Log turned villainous when a bottle of Rage was spilled on it, much like the one the Lumberjack drinks. This is proven from his description and one of the loading screen tips, saying "The Lumberjack and the Log go way back."
The Lumberjack has the highest damage per second out of all Legendaries (Excluding the Inferno Dragon once it reaches tier 3 damage), and overall one of the highest damage per second troops in the game.
The Lumberjack is the only troop that drops a spell upon dying, while the Electro Wizard is the only troop that can be considered to drop a spell (Zap) upon deploying.