This is a brief guide on a setup for playing Olaf in the top lane.

Olaf is melee bruiser with high damage and sustain viable in both top lane and jungle. His huge damage in 1v1 situations coupled with unmitigated true damage from Reckless Swing and boosted power at low health makes him one of the strongest all in duelists in the game. He can be a real lane bully at top lane and is an effective carry laner.

A tanky build works best on Olaf as his kit is best in extended fights so he needs to be survivable, though lifesteal damage items such as Blade of the Ruined King and Ravenous Hydra are strong on him both in lane and teamfights as long as you have the resistances and health to survive initial burst damage.

I'm SpawnOfHell. I'm known as Artemius I in game. I'm a Diamond tier player, though currently not in the higher divisions. I specialize mostly in playing top lane.

Runes might be a little unusual, but I'll justify my reasoning for using them below.

Ghost

Olaf needs Ghost. It's an incredibly important summoner spell on him because he is generally prone to being kited as he lacks gap closers and if he misses Undertow his opponents have a long window of time to escape. Since Olaf can become immune to crowd control for a guaranteed period of time, he can benefit from the entire duration of Ghost without fear of being disabled.

Ignite

Burn, baby, burn. Ignite is a useful spell for snowballing lane, which Olaf is very good at since few top laners are capable of matching his raw damage. Harassing with Reckless Swing then going for an all in with Ragnarok can net you a kill, but often you might need Ignite to finish the job.

Flash

Flash is only an option on Olaf in very specific situations. It's not a good replacement for Ghost because Olaf is not very bursty, so the most you can get from Flashing on an enemy is another autoattack and maybe a Reckless Swing. However, you may need it against impassable terrain from champions such as Jarvan IV, Anivia or Trundle since Ragnarok doesn't help you against those abilities. Replace Ignite if you need Flash.

Berserker Rage

Monstrous passive. This gives you an absolute ton of attack speed as your health decreases. Works really well with the rest of Olaf's kit, since it means more attacks, more lifesteal, faster reduced cooldown on Reckless Swing, more Blade of the Ruined King hits, etc. With this, Tough It Out and Blade of the Ruined King it's not out of the question to have up towards 2.0 to 2.5 attack speed when low.

Undertow

Olaf's crowd control ability. Learn to aim it. It's a fast moving projectile but it hasn't got the best width, and the animation can be misleading. Either way, it's a very strong slow and form of harass when levelled. With max CDR, the cooldown of the ability is 4.8 seconds. Picking up the axe lowers the cooldown by a flat 4.5 seconds, so this means picking the axe up after throwing it allows you to toss another one immediately, allowing you to permaslow enemies. It's also your only form of AoE, so use it to waveclear. Max this second.

Vicious Strikes

Attack speed steroid and sustain ability in one. Activating this ability after trading in lane allows you to heal a lot very quickly. It also acts as a semi- Spirit Visage passive as your health decreases, meaning so long as you are not Ignited you're going to heal a ton keeping you alive while at really low health. Max this last, as it's a good one point wonder.

Reckless Swing

Kaboom. Olaf gets to play Thor and blasts the enemy with lightning bolts from the sky. This ability does true damage, so no amount of armor will reduce its damage output. It also has slightly above autoattack range, so you can hit people with it from beyond their ability to melee you. It costs no mana either, so you can harass freely with it. Sure, it costs health, but that's what the sustained setup is for. Max it first, the cooldown goes down and the damage gets monstrous.

Ragnarok

Olaf intakes an overload of testosterone and becomes immune to crowd control and gains a massive boost to his attack damage, at the cost of his free resistances. This ultimate is amazing. Turn it on, charge at your intended target, and there's nothing he or anyone else can do short of focusing you down and hoping you die before they do. You get a few valuable seconds to run rampant in teamfights and become unstoppable, so use that time wisely. Obviously rank it whenever you can, the extra resists and increased AD is neat.

Health, AD and sustain. What's not to like? With the nerf to Doran's Shield, Doran's Blade is my preferred item to start on Olaf. Together with life steal runes, you can sustain very well even without potions as long as you're not being zoned. This is important, as you need to mitigate the damage you deal to yourself with Reckless Swing.

The best damage item for Olaf, hands down. Attack speed is great on him since it reduces the cooldown on Reckless Swing, it gives some AD which doesn't hurt, and lifesteal is self-explanatory on why it's great. The passive in addition gives your opponent some trouble in itemizing. If they stack armor, Reckless Swing wrecks them. If they stack health, BotRK wrecks them. Rushing both? Well, it'll take them some time to get there, and it doesn't diminish the other things this item offers Olaf.

Tenacity on Olaf is as good as on any other champion. Yes, you have Ragnarok and that makes crowd control a non-issue for its duration, but it doesn't last forever, nor is it a good idea to activate it right away in teamfights. Mercury's Treads is still a good item in those situations where you might want to hold on to your ultimate while chasing a target who can disable you.

This item is a core contributor to my CDR Olaf build. It's massively cost efficient, but isn't a popular item by that alone. However, on Olaf it can work wonders, since the base damage on Reckless Swing and Undertow are very high so having the CDR to spam them gives Olaf a surprising amount of damage. Aside from that, spamming Undertow can get pretty costly so extra mana helps, and the armor together with an AS debuffing passive means you're not going to lose a duel to any melee AD champion.

Good stats, and the passive means more power for Tough It Out and the lifesteal from Blade of the Ruined King. When you have this item and Frozen Heart, you have reached the CDR cap and can proceed to wreck face. This item synergizes with Olaf so well that it should only ever be replaced if you absolutely need Banshee's Veil instead.

Good option for when the enemy team has several AD champions, more effective when they are at least somewhat auto-attack reliant. Since Tenacity isn't absolutely essential, there's nothing keeping you from purchasing these when you want to dive carries while reducing the damage they deal to you. Obviously switch out Mercury's Treads for these.

Very very niche item, but since Olaf is very mobility reliant it has a place on him. It provides no defenses so I can't really recommend it in most situations, but if you're already so ahead you don't care about the bit of resistance other boots give you can get this. That is a very rare situation however.

Olaf's second best offensive item. It provides more upfront damage than Blade of the Ruined King does due to the extra AD, but doesn't give any attack speed, and has less single target damage than BotRK against high health targets. Regardless, the damage it gives is welcome and it is a good item to get if you're fed and required to carry.

This item gives a lot of armor and health, making it naturally welcome on Olaf. The active is also easily applied in teamfights since you want to charge through the enemy team so it can act as a pseudo-initiation. The passive also punishes ranged AD who try to kite you meaning either they get slowed and take damage cut or they run without dealing any damage to you.

Very good item, gives dual resistances, but it's not very cost efficient. What makes it good is its passive, which gives you a safety belt for when you dive carries. You're already very hard to kill, and Guardian Angel means that spending effort on focusing you becomes more disadvantageous since you have the tankiness and sustain to get up for round 2. Another good item if you're carrying.

Used to rush this item before I started running CDR Olaf, not so much anymore ever since I found that Frozen Heart gives stronger trades at the cost of some bulk and AoE for pushing. It's still very good on Olaf but doesn't fit my intent behind this build. Still, it's a good item if you're planning on pushing a lot and is better than Frozen Heart versus certain top laners such as Darius.

A pretty good item, but for Olaf it's inferior to Spirit Visage, and there's rarely a situation to fit both into your build. However, if you find that you need Zephyr and will therefore pass the CDR cap with Frozen Heart, you could purchase this instead in order to keep your build efficient. The spell shield can save you from some pretty nasty things, and possibly let you hold off on using Ragnarok until it is popped.

Gives a ton of armor and punishes autoattacking champions for trying to attack you, again great for when you're diving carries. However, Randuin's Omen is probably more useful most of the time since you should be able to beat a carry without the help of this item's damage, and the slow helps you catch up more easily. Buying both is conceivable if the enemy AD is a huge threat though.

A huge chunk of health and regen, though nothing else. Rarely an optimal item, though it goes well when you're already heavy on resistances and could be a viable 5th or 6th item. Health is good on Olaf since it increases the threshold of his low health benefit abilities.

Good item on Olaf if you went with Ninja Tabi or even Boots of Swiftness but need Tenacity. Attack speed, movement speed and AD make this a decent offensive item, but unfortunately: with Frozen Heart and Spirit Visage, it goes over the CDR cap. As stated before, consider using Banshee's Veil instead of Spirit Visage if you want 100% cost efficiency or buy it anyway if your need for Zephyr's stats is just that great.

Items I commonly see Olaf players buy at lower level games:

Admittedly, this isn't bad if you aren't that great at landing Undertow, but it's completely redundant to buy it if you are. I could see this as a viable item if you're just starting with Olaf, but there's no reason to have a melee permaslow when you have an ability which lets you slow for a distance instead. And honestly, you should just learn to aim axes from the get-go without having to resort to this. Avoid it if you're practiced with Olaf.

No no no. Don't buy this on Olaf, or anyone for that matter. You are not crit-based, and if you want AD, buy AD. If you want armor, there are several armor items which are actually good on Olaf. This item encourages you stack health instead of resistances, which is a huge no in most cases.

Ehh I'll admit Trinity Force isn't a bad item on Olaf, but I don't see its merit as a damage item over Blade of the Ruined King. Ravenous Hydra also gives more raw damage than this, so it's suboptimal if not bad. There are simply better items to get.

Playing Olaf is relatively straightforward, though it's not the easiest thing ever. He's got some demands on the player both mechanically (landing Undertow) and in game knowledge (focusing the right target, initiating fights, etc.) Basically, your tankiness and damage along with CC immunity from Ragnarok pretty much allows you to do what you like, and if the enemy is forced to respond to you then your team will have a much easier time following your charge.

Laning Phase

Olaf's laning is pretty much rinse and repeat. Against melee laners, focus on last hitting with autoattacks and Reckless Swing the enemy laner in the face if they ever get in range. Don't walk forwards trying to Reckless Swing them, it's too predictable and they'll prepare for it if they're smart. If they try to counter attack, pop Tough It Out and bash their face in. If they try to run, you can toss an Undertow and get in some harass, possibly getting off another Reckless Swing if it comes back up. Avoid pushing without wards pre-6 since you don't have escapes or Flash, but once you have Ragnarok you become hard to gank (not impossible though, so don't be suicidal). Just play conservatively and take every opportunity to punish the enemy laner for getting anywhere near you.

Teamfighting

Olaf can play primarily in two ways in teamfights. Either he dives the carry and takes them out with his raw damage or at the very least zones them from the fight, or he protects his own with his permaslow from Undertow and damage from Reckless Swing. If the enemy carry is a huge threat and yours is protected, be the carry diver. If your carry is useless, be a carry diver. If the enemy team has champions who straight up want your carry's n*ts, primarily assassins and champions like Shyvana, play the bodyguard. If your carry is fed and can 1v5 their team through damage, play the bodyguard. These two roles for Olaf are pretty simple, you just need to know when to alternate between the two of them.

Basically a very short guide on my way of building Olaf top lane. This was done relatively quickly, though a lot of planning went on beforehand. If enough people get interested I'll expand this guide with more gameplay detail including matchups and mechanics with Olaf to match my Tryndamere guide.

If you feel that this guide is lacking in information, feel free to tell me what you feel should be included and even downvote if necessary, though I insist on knowing what exactly I need to add.

Thanks,
SoH