Hi all, need some help deciding if and when I should multi class my Paladin. 

My character is based off an Ancient Greek hero in hoplite armor (Dory, Aspis, Xiphos, Breastplate, Greaves). He is devoted to serving the Greek Goddess of Athena. Think of a mix between Achilles with the legend of Hercules. 

So far, he is a level 4 Paladin with an Oath of Glory (TCoE) and not your typical Paladin buildout so I think multi-classing at some point to Fighter would allow him to benefit from the extra attacks and actions, second fighting style, champion sub class, etc. Lots of defence and protection and aiding the party. 

Just wondering if I took Paladin to 8 then multiclass or if I should do it sooner? Thoughts?

First, the extra attack feature does not stack. So a pal5/ftr5 only gets 2 attacks a round, not 3. Only way to get 3 is ftr 11.

If I were to do it, I would probably just 2 levels for the action surge and fighting style. You could also argue for 3 for a subclass and maybe 4 for a feat. 

However, I would not multiclass. You end up with fewer and lower level spell slots, fewer auras, push back your asi. Paladins are really strong single class. I don’t think it’s worth the trade off. 

Even though I’m not going for a typical spellcasting Paladin?

Paladins only cast a few buff spells typically anyway, the rest of their slots are spent smiting.

Pushing back your class features would probably be less than ideal.

I wouldn't consider multi-classing unless I have a very specific reason to do so.  By that, I mean something I directly intend to add to my character.  The reason why, is that multi-classing has a cost in delaying class features and progression.  What you're picking up, has to be worth what you're delaying.

For example, one character I made was a multi-class warlock/sorcerer.  It's a power combo, but I didn't use it in the manner in which the true power was found.  I found, that it was a mistake for how I played it.  My two levels of warlock made me unable to cast my third level spells until level 7.  I didn't get my stat increase until level 6.  In exchange, I got a couple of short rest rechargeable 1st level spell slots, eldritch blast, and agonizing blast.  Since I wasn't trying to be an EB spammer, it was a mistake.  In another warlock multiclass, I took some levels of bard.  I didn't mind delaying what my primary or warlock gave me, so it was a good tradeoff.  But that's why asking yourself what you're getting out of it is important.  There's no free lunch.

As for a paladin?  I'd be wary in watering it down.  How many levels of fighter are you wanting?  What are you wanting out of the fighter?  Every level you take of fighter is delaying a level of paladin, so, those fighter levels have to matter.  if you're not exactly sure what you're delaying for, you should not delay.  For example, with fighter to pull ahead of paladin you'd need 11 levels of fighter to attack 1 more time than a paladin gets.  And because you're already level 4 paladin, instead of attacking twice at character level 5 (pal 5), you wouldn't be able to attack twice until character level 9 (Pal4|Fighter5) and wouldn't get the fighter's third attack until character level 15 (pal4|fighter11).  All the while, you will be stuck with pal 4 spell slots, no paladin aura, etc.

I would just dip two levels in fighter. You could always go swords bard. Swords bard may be better because you can get an extra fighting style and flourishes. Not to mention you could role play as if you practice the art of sword who travels showing off and telling of his great deeds. You also will not miss out on spell slots although you wouldn’t want to go far enough in swords bard to get the redundant extra attack.

If I was dead set on Multiclassing it would be Hexblade for 3 levels, but that’s just me.

I feel like swords bard fits the theme better.

I originally took paladin because of the oath of glory and his divinity with the goddess Athena. He is an Aasimar so he comes from celestial / half blood. 

He apprenticed as a blacksmith, but to be historically accurate was a hoplite in the village militia and has fought in countless battles to protect his village and state.  He became a  folk hero background as he slayed a mythical chimera, and it was in that encounter, near the brink of his death, Athena came to him and revealed his divine heritage. He then slayed the beast and became well known. 

Now, he is on 10 quests for Athena ( sort of like the 10 labors of Hercules) in order to become immortal and join the gods of mount Olympus. 

So Paladin was the answer except I’m not a spell casting paladin. More of a fighter paladin hero type character. So I feel the extra fighting style etc might be worth it. 

The thing is, mostly in play, paladins don’t cast many spells. They just use the slots to smite. It would be easy to play a pally who doesn’t cast anything ever and you’ll still be very effective. 
And then you can always go and use a slot for find steed, but flavor it as a gift from your god. 

But, hey, fighters are super fun, too. You could always go pure fighter. It’s just the m/c benefits of ftr/pal aren’t too great compared to what you give up, imo.

Playing a paladin with the "spell slots=smite slots" mentally works just fine and all, but playing it as a half-caster works wonders too. 

Using your action to cast bless on the first turn (or even pre-casting it before combat if you're able) is a fantastic use of your action and slot. If you want to keep it flavored as fighter as much as you can, re-flavoring bless as a rousing war cry is equally valid.  Then later on when you get aura of protection, you and your allies have fantastic saving throws! SS/GWM build players will love you. A cleric will be happy to jump into spirit guardians right away! And so on, and so forth. 

Anyways, back to the question at hand, multi classing into fighter after lvl 6 is a good idea for action surge. Whether you want to be spell casty or not, having access to action surge is a worth while investment. Gives your damage a huge bump even if you forgo smites. And comes back on a short rest. There's possibilities for lots of things. 

Quote from Xalthu >>

First, the extra attack feature does not stack. So a pal5/ftr5 only gets 2 attacks a round, not 3. Only way to get 3 is ftr 11.

If I were to do it, I would probably just 2 levels for the action surge and fighting style. You could also argue for 3 for a subclass and maybe 4 for a feat. 

However, I would not multiclass. You end up with fewer and lower level spell slots, fewer auras, push back your asi. Paladins are really strong single class. I don’t think it’s worth the trade off. 

 Not only are paladins a strong class, but the most popular paladin multi-class builds bring in spell slots with the class you're going into (often sorcerer or warlock).  You aren't going to want fewer spell slots, than what being a half caster already has imo.