Jill Biden's teaching career spanned 40 years. Sarah L. Voisin/The Washington Post via Getty Images A surprising number of US presidents and first ladies have worked as K-12 teachers. Some briefly taught as a way to make ends meet, while others devoted their careers to teaching. Two presidential couples both worked in K-12 education. Former first lady Jill Biden frequently cited the motto, "Teaching isn't just what I do, it's who I am." Biden is perhaps one of the most notable teachers to occu