Butler, Actor, Researcher, Advisor, Confidante and Father Figure.
Alfred has proved to be the most important person in Bruce Wayne's life. He's the Bat-family's biggest support. Who is he? Why has he proved so special to Batman and his allies?
Alfred Thaddeus Crane Pennyworth is Bruce Wayne's Butler. After the death of Thomas and Martha Wayne, he became Bruce's legal gaurdian till the time that he was a minor.
Alfred is from England, and is often portrayed as a caring, loyal, intelligent confidante to Bruce Wayne, with a penchant for wisecracks and witty comebacks. He is one of the most popular characters in the Batman universe. In some stories, he was portrayed as a retired actor, and some as a former memeber of the british special forces. He is the only member of the bat-family who uses a gun to defend himself (and others), and this is tolerated by Bruce Wayne (his preferred weapon being a shotgun). He of course, knows that Bruce Wayne is Batman, and is often provides vital tactical, intelligence, and medical support to Batman. Apart from that, he also plays a vital role in covering for Bruce Wayne so that Wayne could maintain the public persona of the billionaire trust-fund kid.
He was introduced in 1943 as part of Batman #16. It is generally recognized that writer Don Cameron came up with the character along with Artists Bob Kane and Jerry Robinson. Later, the character and his backstory was heavily revised by Bill Finger.
In the initial days, Alfred was portrayed more as a comedic character who stumbled his way through solving crimes by accident. He was quite portly and chubby, and his clothing ensemble resembled something like Sherlock Holmes. Later in the 1943, the Batman serial was released where the character was performed by a much thinner actor (William Austin). DC then decided to make Alfred thinner in the comics too.
In those early days, it was shown that Alfred just showed up at Wayne's doorstep and asked to be his butler. Later on, Batman and Robin reveal their identities to him, and he starts to assist and support them as crimefighting as well.
In the early eighties, Alfred's origins recieve a change. Instead of him being a butler who joins Bruce Wayne later on, he is portrayed as his legal gaurdian who raised Bruce Wayne after the murder of Thomas and Martha Mayne.
He is also shown to have a background of both a former british intelligence officer who helped refugees escape Nazi concentration camps during world war 2. After the war, he got tired of all the violence, and took up theatre acting. During this time, his father got ill, and to honor his father's last wish, he travelled to the United States to serve as the Wayne Butler. There, he discovered that Wayne and Grayson as Batman and Robin, and vowed to keep the secret and serve them.
Post-crisis (after 1986), it is shown that Alfred had been the Wayne family butler since the time of Thomas Wayne, and when Bruce's parents died, he became Bruce's legal gaurdian till the time he reached legal maturity. All the while serving as his father figure, confidante, and advisor.
Alfred has a charming and wisecracking personality. Though his humour often makes fun of the other person, it is more meant to lighten to mood or display his sarcasm than to cause any genuine conflict.
However, apart from his wisecracking nature, he genuinly loves and takes care of Bruce Wayne and his wards, and tries, at all times, to make sure they are cared for in terms of mental and physicall well-being.
He also wants Bruce Wayne to have a life outside of Batman, and from time-to-time tries to convince him to go out on dates. Deep down though, he realises the tragedy of it, and knows that most probably Bruce will never settle down with any girl and have a normal life with a family, and will probably go out saving the city as Batman. The last few panels in Scott Snyder and Greg Capullo's Zero-Year and Endgame stories highlight this aspect the best.
He has been most prominently portrayed by Micheal Caine in the Batman movies directed by Christopher nolan, namely, Batman Begins, The Dark Knight and The Dark Knight Rises. Unlike previous movie depictions of the character, Caine's role is more deep, and he regularly provides advice and support to Bruce Wayne/Batman and most occasions.
In the movies from 1989 to 1998 Micheal Gough played the role of Alfred, but his part was never of any real depth as such, unfortunately.
In the TV Show Gotham, the part is played by actor Sean Pertwee, whose performance had been universally lauded. His take on Alfred seems to be based on Geoff John's Batman: Earth One Alfred, which has a background in combat.