Alfred Beagle, last name later changed to Pennyworth, according to:
http://www.dccomics.com/blog/2014/07/22/batman-at-75-highlights-in-the-life-of-the-caped-crusader
Starting with Detective Comics 38 in April, 1940, Batman was joined by his crime fighting partner, Robin the Boy Wonder (Dick Grayson). Batman and Robin were later joined by their faithful butler, Alfred (his last name was Beagle and later changed to Pennyworth), in Batman 16 in April/May, 1943.
The team of Batman, Robin and Alfred became the nucleus of the Batman stories during the 1940s, 50s and early 60s. Police Commissioner James Gordon was also a constant character in the adventures of Batman and Robin, however, he did not know that Batman and Bruce Wayne were one in the same. He first appeared in Detective Comics 27. Other regular or semi-regular characters included Vickie Vale, Batwoman (Kathy Kane), Bat-Girl(Betty Kane - golden age), Bat-Mite, Bat-Hound (Ace), and Professor Carter Nichols.