once again, there will be FF7 spoilers, so if you don't want to see those, scooch along.
...anyone still with me? all righty. i'll explain this in simple terms to avoid the Dreaded Wall of Text. you can listen with TTS if you want.

Pre-Compilation

honestly, i barely know anything about his backstory. there's a LOT of conflicting info about his age and stuff. he's been 21, 25, and 30 at the same time somehow... so i usually assume he's 27, which would make his birth year 1980 by my standards (zamn!), since FF7 takes place in 2007.
in On the Way to a Smile, you can get a teeny glimpse at what his life was like as a kid. it wasn't very fun, and that's an easy conclusion to make. his mother died around this time as well - and hey, you thought HE was a huge jerk?! wait till you get a load of his DAD. that guy's known as President Shinra throughout the games.
during the book, Rufus recounts a time when he couldn't sleep and came across his usually-absent dad, who- instead of telling him to go back to sleep- showed him blueprints of the Shinra Building's presidential suite. concerned about how safe it was to be 70 stories up without an escape route, he suggested it, hoping it would garner some praise... instead, he basically got ridiculed for the idea. ouch. good news, though: it was included in the final design, labeled with an L "for 'Loser'". remember that now, it'll be important later.

Before Crisis -Final Fantasy VII-

i had to watch an entire playthrough of this game to understand what happened here (you can find it on my FFVII Excavation blog). this game and Crisis Core overlap with one another, so i might put the same information in both. quick explanation, you work in General Affairs (more commonly, you're known as a member of the 'Turks') for the Shinra Company. you do alll the protecting and the dirty work, and you're fighting Avalanche, an anti-Shinra terrorist group.
he's in the game pretty early- he praises you, the Player Turk, for your skill. yes i squealed and giggled at that scene. ANYWAYS MOVING ON during a rocket launch you're tasked with protecting him during the big event. when you gush over how exciting it is, he tells you that he hates it, believing it's a waste of money and resources on something useless. what a pessimist!
as you complete missions everywhere, you eventually notice that Avalanche is a little too in-tune with where you're going next, as they ambush you at nearly every opportunity. the executives at Shinra have several meetings and Rufus constantly brings up that there must be a mole.
guess who the mole is?! i want'cha to guess REALLY hard.
ready? if you guessed Rufus Shinra, DING DING DING you are correct! this little snitch was funding Avalanche & giving them information the whole time, and when he's betrayed by them (damn thats tough), the Turks capture him. he gets put under house arrest- i call it the Time-Out Chair- under the jurisdiction of his father, and it's framed as a "long-term business trip". Rufus is released just in time to save the Turks from being executed for being a liability to the company- in other words, a liability to President Shinra. hate him yet?

Crisis Core -Final Fantasy VII-

he's mentioned a few times in this game, but never shown. the first instance is in an e-mail notice. Rufus is promoted to VP and Corporate Officer in this notice, but also stated to have gone on that "long-term business trip" i told you about, AKA the Time-Out Chair.
the second time he's mentioned is in an e-mail from SOLDIER Director Lazard. SOLDIER is Shinra's elite military unit. it's very vague, but he A) explains 'ill blood' in parental bonds, and B) says that the President and Vice President have to confront "Shinra's shadows", the issues that have arisen due to the company's rapid growth.
so wait a minute!! "why is this random dude tied to Rufus so closely?" "why should i care about Lazard??" i hear you asking. well, he's actually Rufus's older half-brother. in other words, President Shinra is a sleaze. nobody likes him.
someone in the city hints at this, and when Lazard later resigns from the company after being exposed for embezzling funds, one of the security guards tells you that he resembled the VP a liiiiittle too closely for comfort. your friend Kunsel also e-mails you, suspecting he was after Rufus's position. i don't think that's how you get promoted, buddy...

Final Fantasy VII

i'm gonna be as simple as possible here. as the main entry, this game has a LOT to sift through. i assume most people reading this don't know much about FF7, so hopefully you can sit through this without falling asleep. honestly, if you're still here, i'm surprised.
GOOD NEWS!!! President Shinra gets skewered in this game! great, i hated him. this means our main man gets promoted to President. BAD NEWS... he's gonna go on a major power rampage. a parade celebrating his promotion occurs, and Avalanche (tables turned, Avalanche is now the protagonist) sneaks into this parade. it's got a bomb ass theme, by the way.. click here to listen.
Sephiroth is the real bad guy in this game, and Shinra's just obstacle number one. Rufus wants to stop Sephiroth so Shinra can stay in power, and Avalanche wants to stop Sephiroth because he's trying to destroy the world. our newly-appointed President screws up a little bit later on. Aerith dies by Sephiroth's hand, negating any chance of him being stopped, and he summons Meteor, the ultimate black magic which will basically annihilate the world and make him a god. Rufus tries to stop him anyways by first shooting that same rocket mentioned earlier at Meteor. that makes it worse. then he tries shooting a giant mako cannon at the Northern Crater where Sephiroth is hiding out under a forcefield.
good news: it got rid of the forcefield! bad news: a giant monster trying to protect the Planet called 'Diamond Weapon' gets caught in the line of fire and destroys the Shinra Building with an attack. Rufus is in that building. not good. there's NO way he isn't dead, right?

Final Fantasy VII: On The Way to a Smile

remember the L for Loser that i mentioned way back? it comes into play now. Rufus uses the escape route he suggested as a kid to avoid dying to Diamond Weapon. he breaks a painful amount of bones on the way down, but realizes a lot of things regarding his relationship with his dad that make him rethink his decisions as President. mostly that he had been going about everything the wrong way, and he had to come to terms with that. he didn't hate his old man as he'd always insisted- really, all he wanted was for President Shinra to respect him, but "incurred his wrath rather than his respect" with his actions because he didn't know how to express this desire. and even after the guy died, Rufus was still trying to one-up him for no reason other than to believe he could gain this same respect from somebody other than himself.

his ability to come to terms with that is what made me love him so much.

Meteor is stopped. Aerith had summoned Holy, the ultimate white magic, before she died, preventing Meteor from doing too much damage. after being taken to safety, Rufus gets kidnapped a few times. everyone HATES Shinra at this point, and they all want him to either help them with their crazy plans or give them reparations. mind you, Sephiroth caused all of this destruction. Shinra's just getting the tail end of the anger because they ran everything, and their power is gone now, by the way. so Rufus's power over the world is also gone, yet he's still getting tortured left and right for virtually no reason. to make things more unfortunate, he contracts Geostigma, a disease caused by the after effects of Meteor. he's eventually rescued by the Turks and taken to Healen Lodge, a Shinra-owned hospital up in the mountains. he and the Turks live there from now on. it's nice, i'd live there too...

Final Fantasy VII: Advent Children

he secretly has a box with Jenova cells, which the 3 Remnants of Sephiroth want- Jenova is an evil alien thing that Sephiroth and them think is their mother. they are VERY attached to her and want this box very desperately. Rufus trolls the leader, Kadaj, by making him think he's a crippled dude with nothing to hide.
midway through the movie, he reveals he's perfectly fine and has the box, which he throws off a building. Kadaj tries to kill him but misses. Rufus jumps off the building, prompting Kadaj to jump off too. as they fall, Rufus shoots the box. Cloud stops Sephiroth for the second time. Everyone with Geostigma, including our favorite President, is cured because of Aerith's ability to cast healing magic even after her death. we love Aerith!!
simple, right? not really? well, i tried.
P.S. he's got another brother.. his name's Evan, but he's not important lol

Dirge of Cerberus -Final Fantasy VII-

he's barely in this game. at the very beginning, when Meteor is coming, he's shown being carried out on a stretcher for, like, 0.5 seconds.
also, there's a new company in town called the World Regenesis Organization (usually shortened to WRO because that's not a mouthful). they hate Shinra like everyone else, yet he's hinted at to be the one funding this company, but that's his only mention in the entire game. maybe that's why it sucked.

aaand that's all we know about him. if you somehow got to the end of this, bless you for listening to this. in hindsight, i did not avoid the Dreaded Wall of Text... but it's because i really love this guy and wanted to make it as easy as possible for non-FF7 players to understand him. he's Public Idiot Number 1 but he's got a lot of charm. i can only recommend that you play FF7 from here if you haven't already.