Alyson Hannigan: Alyson Hannigan. Actress: Buffy the Vampire Slayer. Alyson Hannigan was born in Washington, D.C. to Emilie (Posner), a real estate agent, and Al Hannigan, a truck driver. She began her acting career in Atlanta at the young age of 4 in commercials sponsoring such companies as McDonald's, Six Flags, and Oreos. She is a seasoned television actress, guest starring in Picket Fences (1992), Roseanne (1988), Touched by an Angel (1994)...