Galio is always a pretty great pick as both support and mid, with a versatile kit that provides CC, damage and tankiness. In fact, it is so versatile, that he can very easily be played jungle, like quite a few other support champs. His ganks are easy and strong, especially in the early game, his W passive gives him early and easy tankiness, and his CC and ult mean he plays a crucial role throughout the entire game, and can easily work as a replacement tank support. While I haven't played too much of it yet, it's already proven itself a great pick that your enemies won't expect or know how to play against.

Pros

• Strong early ganks
• High early tankiness due to W passive
• Can act as stand-in tank support
• Great teamfighting
• Easy to learn
• High sustain
• Doesn't fall off too hard at any point

Cons

• Slow and difficult jungle clear
• Bad at taking objectives solo
• Fairly low damage after early game
• Most abilities don't scale with HP / Armour / MR
• Easily invaded

Main Path

Get a hard leash from your laner for Red Brambleback and smite it, skip Ancient Krug and go straight to Raptors, which are easily taken without smite due to Galio's passive, Q and E (his E in particular does a lot of damage to the smaller Raptors). Then you can do Wolves and Blue Sentinel without trouble, and by the time you get to Gromp you'll have smite back, so you can smite it and pop a Refillable Potion to get back to practically full HP.

Alternate Path

An alternate clear path against hard invade junglers with early game power such as Graves, Lee Sin, Xin Zhao and others is to simply do Red Brambleback with a hard leash and then go straight to Blue Sentinel and smite it. From there, you'll be able to get to full HP from Rift Scuttler and / or Honeyfruit, and go straight to a gank from there.

Aftershock

Obvious, as Galio you're going to want to be in the middle of a fight, so the AoE damage from Aftershock is best.

Font of Life

Strengthens early ganks and works well into your role as a supportive jungler.

Bone Plating

Generally a better early game rune, but your strong early game is what you're banking off of. Allows you to chase in ganks and win or go even in 1v1s easier.

Overgrowth

Extra HP is always great on a tank, and without any healing or the need for tenacity, considering you have a dash, it's the best choice out of the runes here.

Transcendence

Very good rune in general, gives you a lot of ability haste early and scales very well into late game.

Waterwalking

Allows for quick ganks, better objective taking and 1v1s with the enemy jungler and running in range of a teammate to ult them.

Other Options

Demolish

You're building a fair amount of HP, as it comes alongside most items you'll be building, so Demolish is a decent choice if you need some extra pushing potential in your comp, but not having Font of Life is a pretty big hit to your early game especially.

Nimbus Cloak

Allows you to chase enemies that can kite you, both in ganks, 1v1s and teamfights.

Gathering Storm

Allows for better mid to late game damage, although this isn't really needed on a CC heavy tank like Galio.

Absolute Focus

Being a tank, you'll often be above 70% HP and getting this bonus, plus the extra early game AP is nice, but as with Gathering Storm, you don't really need the bonus this provides playing this champ.

Innate: Galio's next basic attack becomes unstoppable and deals 15 − 200 (based on level) (+ 100% AD) (+ 50% AP) (+ 60% bonus magic resistance) total magic damage to its target and all enemies around it. Colossal Smash can critically strike, dealing (75% AD) bonus magic damage to all targets hit.

Active: Galio creates two windblasts 250 units to either side of him that arc out before converging to the target area, dealing magic damage to all enemies they pass through. Gust Magic Damage: 70 / 105 / 140 / 175 / 210 (+ 75% AP) When the blasts meet, the gusts form a tornado that persists for 2 seconds and slowly moves forward, dealing magic damage every 0.5 seconds to every enemy within, with the target's health ratio capped at 150 damage against Monsters. Tornado Magic Damage Per Tick: 2% (+ 0.66% per 100 AP) of target's maximum health.

Passive: Upon learning Shield of Durand or after not taking damage for 12 seconds, Galio gains Anti-Magic Bulwark. Anti-Magic Bulwark: Gain a shield that absorbs magic damage. Magic Damage Shield: 8 / 11 / 14 / 17 / 20% of maximum health Active: Galio charges for up to 3 seconds, slowing himself by 15%, and gaining magic damage reduction and half of that amount as physical damage reduction; charging increases Shield of Durand's radius, damage and taunt duration over the first 2 seconds of the channel. Shield of Durand can be recast at any time within its duration. If Galio finishes charging or is interrupted, he automatically initiates the recast. Magic Damage Reduction: 20 / 25 / 30 / 35 / 40% (+ 5% per 100 AP) (+ 8% per 100 bonus magic resistance) Physical Damage Reduction: 10 / 12.5 / 15 / 17.5 / 20% (+ 2.5% per 100 AP) (+ 4% per 100 bonus magic resistance) Recast: Galio refreshes the damage reduction for 2 seconds and deals magic damage to nearby enemy champions, increased by 0% − 200% (based on channel time), and taunts them and sets their Movement Speed to a static 60 for 0.5 − 1.5 (based on channel time) seconds. Minimum Magic Damage: 20 / 35 / 50 / 65 / 80 (+ 30% AP)

Active: Galio steps backwards in the opposite direction and, after the cast time, he dashes to the target location, though not through terrain, until he collides with an enemy champion. Galio deals magic damage to all enemies hit in his path, reduced by 50% against non-champions, and knocks them up for 0.75 seconds. Champion Magic Damage: 90 / 130 / 170 / 210 / 250 (+ 90% AP)

Active: Galio designates the target allied champion's location at the time of cast as his landing spot, resetting Shield of Durand's passive magic shield for himself and additionally granting it to all allied champions in the area he casted it at for 5 seconds, and channels for 2.75 seconds. After 1.25 seconds of the activation, Galio becomes untargetable and immune to crowd control then leaps into the air for 0.85 seconds before dashing to the location over 0.25 seconds, after which he lands and becomes targetable again, retaining the immunity for 0.4 seconds and dealing magic damage to all nearby enemies on impact as well as knocking them back 100 units over 0.75 seconds. Magic Damage: 150 / 250 / 350 (+ 70% AP)

For your early game, you obviously first want to just do a full clear of your red side, but after this, ideally, you should be attempting a gank. The best lane for an early gank is almost always mid, because most mid champs are very squishy and can't fight you early, ganking mid is almost always very safe and you're always in a perfect position for it at the end of your red side clear. After ganking, or if you can't gank, go for the Scuttle, then clear your blue side. At this point you can attempt another gank, or if you can't, simply back and buy your early items ( Bami's Cinder, Bramble Vest, etc).

Your bread and butter combo, E + AA + W + Q can almost always secure you an early kill or Flash from the enemy laner.

While a jungler's midgame is generally for objectives, on Galio you generally want to just pressure the enemy laners and jungle away from drake for as long as you can. The only way you can get it done properly is with both your ADC and support, so until they've pushed their wave up or gotten both enemy laners to back or die (with your help, hopefully), you don't want to try and get the drake. Luckily, even if the enemies do try and get the drake, Galio is very powerful when it comes to contesting drakes with his W, and, as long as your laners are with you, basically any drake can be successfully contested in the mid game.

Rift Herald is a different story as, with any jungler, it's an easy objective to take, even solo (although it's even easier with your top laner). Ideally go for it when your top laner's wave is pushed up, as it forces the enemy laner to farm instead of roaming or coming to check on the Rift Herald.

Mid game is also when teamfights will begin to start, which, with your ability haste from Transcendence and items, as well as Iceborn Gauntlet which you should almost certainly have gotten by this point, should go in your favour. Ideally you want to E their frontline first, before walking into the team with your W up, letting it fully charge before letting it go and Q'ing. Then, you can simply AA, proccing your passive and Iceborn Gauntlet's passive until you can cast abilities again. After that, what you do just comes down to common sense.

If you aren't in the heart of a teamfight when it breaks out, never forget the power of your R, especially if you have Waterwalking, in which case you can sprint to fights from almost anywhere on the map.

With Galio's lacking damage, especially late game, you don't want to be splitpushing, or even pushing alongside your laners (unless you took Demolish). Always be alongside your laners when they're fighting, since you're playing the role of a support. Ideally, be alongside your ADC as a second support, since they're usually your carry, and a carry from another lane can usually take care of themselves (e.g. Irelia, Camille, Zed, Pyke, etc).

Just like in mid game, your R is a very powerful tool here, especially when used alongside your W. It gives amazing opportunities for your team to take people down with the heavy CC and intimidation it provides. The best time to use your R is when there's a teamfight with at least equal amounts of teammates and enemies and one of your teammates has been engaged on and CC'd. When the first teammate is CC'd, all the enemies will jump on them, and this is true at practically all levels of play, so you want to try and ult them immediately, as the enemies will be too distracted running at your teammate to properly pay attention to you coming in, and will all be close to the centre of the ult, unable to escape. A play like this can turn fights around completely, and is how you will create opportunities to push into the enemy base and win the game.

I don't have any stream or channel to plug here, so all I can really say is I hope this guide helped you out, and I hope you have fun playing with this build. I'm extremely new to Galio, and even newer to Galio jungle, so all criticism is very much appreciated, especailly from any Galio mains or Galio jungle players out there. Best of luck!