Jungle Jax is more than just a viable choice for either ranked or normal as he has a fast jungle clearing time, and a skill that makes him a ganking threat. This guide is NOT to show you how to jungle, but to show you that Jungle Jax is VIABLE as he has a jump to help get closer to his enemies when he ganks and a fast jungle clearing time.

There are many different runes that you can take and most "jungling runes" would be viable for Jax
Ex: Armor pen marks, Armor Seals, CD glyps and Armor pen Quints
However, the runes shown in Kndmursu's Jax Build works best

I take 9/11/10 masteries because they work with jungle jax best. The 11 in defensive mastery allows him to take damage from jungle creeps and also increase his dodge chance as well as his movement speed because of dodge. The 9 in offense allows gold from smite, cooldown, magic penatration, and ability power incerase. And lastly the 10 in utility helps him level faster in the jungle and increase the time of his buffs.

You should start off with five potions and cloth armor because the cloth armor goes into his Ninja Tabi which is essential to his dodge. His dodge is the main reason as to why he can jungle.

You can start at blue golem and work your way down, and you should be able to kill red lizard after the wraiths. It is ideal to get a leash from your teammate but it can be done without a leash.

Q: This will be Jax's main ganking tool once you get red buff. This allows a jump that is similar to Xin Zhao's Audacious Charge. Combining it with his W, it procs a slow creating a devastating attack that does a huge amount of burst damage.
W: When jungling, always use this after you attack a minion as it resets his attack time. Use this before landing your Q to get some extra damage in.
E: This is your main jungling skill as Jax, without it jungle jax would not be a viable choice. With this skill Jax is able to avoid damage by dodging, increase his movement speed because of the defensive mastery, stun around you, and cause a hefty amount of damage. The cooldown on this skill is ridiculously fast and with two plus creeps attacking you, the chances of it coming on is increasingly higher. With this and blue buff your jungling time can easily match olaf and other fast junglers.