Upon death, he drops a bottle of Rage that increases the attack speed and movement speed of friendly troops and buildings in the spell's area.
The Lumberjack is best to be supported with other troops because when he dies, the Rage will make the other troops do great damage. Thus, it is not good to use him alone. For this strategy, place him near or at the front so that when he dies, many of the troops in the push will still survive and undergo the rage effect.
He can also be used defensively. If he is killed near your Princess Tower, the resulting Rage will be dropped on the Arena Tower, increasing its attack speed. You can also capitalize on this by placing other buildings in front of 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 the Lumberjack and the Minion Horde deal massive damage to the tower.
An Ice Golem and Fire Spirits are 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 kill the Minions.
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.
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.
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 the Mini P.E.K.K.A and possibly take out the Mini P.E.K.K.A.
He is also useful for protecting other glass cannons from the Valkyrie due to his high damage per second.
On 24/8/16, a Balance Update changed the Lumberjack's speed from fast to very fast, increased his hit speed from 1.1 seconds to 0.7 seconds and decreased his damage by 23%.
On 19/9/16, a Balance Update decreased the Rage's attack speed boost to 30% (from 40%) and its duration by 2 sec. This also affected the Lumberjack's Rage.
On 1/11/16, a Balance Update increased the Rage's attack speed boost to 35% (from 30%).
On 15/12/16, a Balance Update increased the Lumberjack's hitpoints by 6%.
On 13/3/17, the March 2017 Update increased the Rage's level such that it is now 3 levels higher than the Lumberjack (a level 1 Lumberjack will drop a level 4 Rage, a level 2 Lumberjack will drop a level 5 Rage, and so on).
On 19/4/17, a Balance Update increased the Lumberjack's hitpoints by 4%.
During the Lumberjack's deploy time, he can be seen drinking his bottle of Rage.
He is the only troop that can affect friendly 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.