Yes, but Classic Sub-Zero (from UMK3/MKT) is a non-canon character, and probably isn't Noob Saibot, for his ending, probably was Raiden, Johnny Cage or another character that it wasn't in the MK3/UMK3... but well, it's only speculation, the only thing surely is that Classic Sub-Zero and Human Smoke (from UMK3/MKT) are non-canon characters.

Original Sub-Zero: MK1, MK2, UMK3 (as Classic Sub-Zero)
Sub-Zero's Brother: MK3, MK4, MKDA, MKD
This is how I consider it. This is correct if you do not consider the fact that Noob Saibot is actually Original Sub-Zero.

so the MK2 sub-zero is the 1st sub? And the 2nd sub doesn't come until MK3?

No, no, no. Original Sub-Zero wasn't in MK2 (if you don't consider the fact that Noob Saibot is actually Original Sub-Zero), in MK2 debuted Sub-Zero's Brother, because the Original Sub-Zero was killed by Scorpion in MK1.

classic sub was only in mk1. The sub in mkd is the same one as mk2 3 4 and mkda. Mk1 sub is NOT mk2 sub.

k, thats what I thot... just making sure. By the way... what were Noob's finishers in MK4/MKG? Were they both like Sub's finishers? Or just one?

in Noob Smoke's ending it is revealed that Noob Saibot was the original Sub-Zero.
Original Sub-Zero:
MK1,MK2(Noob),UMK3 and MKT(Noob),MK4 and Gold(Noob),MK:TE(Noob),MK:D(Noob)
Younger Sub-Zero was in everything else. i have heard speculation on this board about classic Sub-Zero being Quan Chi or Shinnok in disguise.

It's easier with pictures I suppose. Original SubZero:





SubZero (Younger):

Wow, I had no idea. I always thought that the Sub-Zero in MK2 was the original, and his brother only came around in MK3. Are you guys sure, because that's what I really think it is... I mean the unmasked one is his brother, and with the scar on his eye... MK2 Sub-Zero has neither of these things. I thought the story was that original was killed only after MK2.

Naw.....that was Sub2 in MK2. He got that scar after MK2 and before MK3....depending on who you ask. Some say Scorpion gave it to him in the MK2 tourny then realized he wasn't the other Sub. And some say it was given by Cyrax or Sektor. So yeah.....it is Sub2 in MK2

it tells in Subbys MK2 ending, it says that Scorpion finds out that this subzero is not the one he is after and he devotes himself to protecting him...

I don't understand why there's all this confusion.
Original Sub-Zero = MK1
Younger Sub-Zero = MK2 MK3+
"Classic" 3rd Sub-Zero = UMK3 MKT
The "Classic" Sub-Zero is neither the older or the younger sub. He is a completley new warrior who's true identity was only hinted at, but never revealed

Sub-Zero's younger brother was in Mortal Kombat 2 so that he could complete his older brother's mission on assassinating Shang Tsung. Sub-Zero was fighting in Shao Kahn's tournament and spared a defeated opponent's life when he was told to finish him.
Scorpion relized then that his sworn enemy was not this person and he returned to the Netherealm.The younger Sub-Zero I think did not even meet Scorpion because in Mortal Kombat 4 there was no mention of Scorpion's oath to protect him.
Sub-Zero did not manage to kill Shang Tsung and barely escaped Outworld with his life. Sub-Zero returned to the Lin Kuei with his mission not complete and that is when he was supposed to be added on to the Cybernetic Ninja program.
Smoke and Sub-Zero did not want to take part in this because they valued their human form. Sub-Zero and Smoke tried to escape the Lin Kuei and Smoke did not make it out of the Lin Kuei with Sub-Zero. Sub-Zero was marked for death by the clan, that is why he has that scar on his eye.

first time I ever heard that. Why do you say that?

I never heard that classic Sub-Zero was different from the first two either, or was a 3rd Sub-Zero. Please do explain how it was *hinted*, as I must have missed that.

Direct quote from Classic Sub Zero (UMK3) ending.

I am still unsure who this is supposed to be BUT my best guess is Johnny Cage, although I cant imagine that being right. But he seems the only possible choice

There are more than just the two Sub-Zero's in the MK games. We have only played as two of them. They were 6th, and 7th generation warriors. The oldest brother's only appearance in MK as a ninja Lin Kuei was in MK1. After that, he was Noob Saibot. His younger brother's first appearance was in MKII, and he has been Sub-Zero ever since. In UMK3/MKT the ninja Sub-Zero is actually one of the new fighters in MK4. The biggest rumor is that it was Shinnok, because Shinnok had the powers of mimicking his opponents. Ninja Sub-Zero's story does say that the warriors are shocked to discover that it was a warrior who has long been missing from a previous MK (not in any MKs before UMK3), and one who will return in the next (MK4). Anyway, there are a total of 7 generations of Sub-Zero(s). The first one was in MK Konquest the series around the same time as Kung Lao, and each one of his decendants was also named Sub-Zero. Sub-Zero in MKD(Sub-Zero 7) is now the Grandmaster of the Lin Kuei.

thats true... there was a lot more Sub's.... look at the MK2 ending... wow. Which brings up something else... MK2 sub was asian... but not in future MK's. I wish they'd keep their ethnicities. Eh, oh well.

Where did Sub-Zero's scar from MK3 go in MK:D? It just disappeared.

Seeing how SubZero never won the third tournament... I refuse to believe his ending. I never knew Cage had mystical Ice Powers. I think this was just some stupid ending Tobais made to get fans excited or something. Classic Sub-Zero was thrown in there probably just for the sake of having a Sub-Zero that had MK2 powers.

Classic Sub-Zero was confirmed as a non-canon character.
Lol Classic Sub-Zero = Johnny Cage ... erm no, Cage doesn't have Ice Powers.

The Sub-Zero that has been in the games since MK2 must be the same as in Deception, because how else would Smoke acknowledge him in Noob-Smoke's ending? Just a thought.
Classic Sub-Zero from UMK3/MKT is one of those *non-existant ending* type deals, along with Human Smoke. Obviously Smoke did not return to being human after that tournament, so the same can be said for Classic Sub-Zero.

I thinbk you guys got most of the points. Sub zero 7 was the one featured from mk 2 onwards. Only in mk1 was his older brother featured.