There're 2 ways to play as him:

• Complete the game with Reiko. Choose Versus Mode and enter the following Kombat Kode: 012012. Then exit the match and enter the character selection screen. Press the Run button on the Hidden icon at the bottom of the screen and select Reiko (Up, Up, Left) by pressing the Block button, while still holding Run. You can also choose him by pressing both buttons simultaneously.



• Enable the Cheat Menu, by going to Options, highlighting ''Vs Screen Enabled'' and holding Run + Block until you hear Jarek laughing. Leave the Cheat Menu and choose Noob Saibot like in the first way.

But can I use him in story mode?

You mean the Arcade mode. Yes, you can, but don't expect any bonus endings.

Can I just tell the OP that his Joker signature is frightening as hell! Dude, your face looks very... um... disturbing =P

You could've told him that in an IM instead of bumping this thread.
Anyway, I've always been able to get access to Noob by beating the game with Reiko, then using the Hidden option and pressing and holding those buttons while selecting Reiko, not using the versus screen code. Not sure if that'll make it easier, but in any case, Mortalman's got you covered.