A long as there has been a Batman, Big Al has been there buttling for him. Alfred was in the 60's Tv series, each of the love-action films and even in the Birds of Prey series. He was also voiced in Superfriends, Batman: The Animated Series, and The Batman.
The Pre-Crisis comics established Alfred as a retired actor and intelligence agent who followed the deathbed wish of his dying father, Jarvis, to carry on the tradition of serving the Wayne family. To that end, Alfred introduced himself to Bruce Wayne and Dick Grayson at Wayne Manor and insisted on becoming their butler. Although the pair did not want one, especially since they did not want to jeopardize their secret identities with a servant in the house, they did not have the heart to reject Alfred.
Initially, Alfred discovered their identities by accident. While fighting a burglar, he accidentally hit a switch and opened a sliding panel leading to the Batcave. His first night at Wayne Manor, Alfred awoke to moaning and followed the sound to the secret door to the staircase to the Batcave and met his would be employers in their superhero identities (Batman had been injured while out in the field). As it turned out, the wounds were actually insignificant, but Alfred's care convinced the residents that their butler could be trusted. Since then, Alfred included the support staff duties of the Dynamic Duo on top of his regular tasks.
Ironically, Alfred's loyalty would lead him to become a member of Batman's rogue's gallery. While pushing Batman and Robin out of the way of a falling boulder, Alfred was seemingly killed. It was revealed that he had been revived by a scientist named Brandon Crawford. His attempt at regeneration resulted in a dramatic change: Alfred awoke from his apparent death with pasty white skin with circular markings, superhuman powers, including telekinesis, and a desire to destroy Batman and Robin. Calling himself The Outsider, he indirectly battled the Dynamic Duo on a number of occasions, using others as his puppets – the Grasshopper Gang in Detective #334, Zatanna in Detective #336, and even the Batmobile itself in Detective #340 – and generally only appeared as a mocking voice over the radio. He did not physically appear in the comics until Detective #356, when he is bathed again in the rays of the regeneration machine during a struggle with Batman, and returns to normal, with no memory of his time as a supervillain.
In the Post-Crisis comics' continuity, Alfred has been the Wayne Family butler all of Bruce's life, and had helped his master establish his superhero career from the beginning. Alfred's history has been retconned several times over the years, creating assorted versions. In one such version Alfred was hired away from the British Royal Family by Bruce's parents, and he virtually raised Bruce after they were murdered.
Meanwhile another version of Alfred's Post-Crisis life was slightly more closely linked to his pre-Crisis counterpart. In this version Alfred was an actor on the English Stage, who agreed to become the Waynes' butler, only so as to honor the dying wish of his father. At the time he begins working for the Waynes, Bruce is but a young child. After several months, Alfred voices the desire to quit and return home to continue his life as an actor. However, these plans are momentarily forgotten when young Bruce returns home, after getting into a fight with a school bully. Alfred teaches Bruce to handle the bully strategically, rather than using brute force and following Alfred's advice, Bruce manages to take care of his bully problem. Upon returning home, Bruce requests that Alfred stays, and Alfred agrees without a second thought. After the Waynes' murders, Alfred raises Bruce.
Alfred would later aid Bruce in raising Dick Grayson, Jason Todd and Tim Drake, all of whom would be adopted by Bruce Wayne and become his partner Robin. He also had close friendships with other members of the Bat-Clan including Barbara Gordon and Cassandra Cain.
Alfred often acts as a father-figure to Bruce, and a grandfather to Dick, Jason and Tim. However, due to his rather cold personality, Bruce Wayne makes sure that at least some degree of the business relationship between the two always exists. He is also highly respected by those heroes who are aware of his existence, including Superman, Wonder Woman, Green Lantern and the original Teen Titans. Alfred has also been romantically linked to Dr. Leslie Thompkins, though his relationship with her never came to anything, particularly after she let Stephanie Brown die from neglect. He also developed feelings for Tim Drake's stepmother, but again, nothing came of it.
The Dark Knight returns in 79 days!