Born Iris Barrel in Astoria, Queens, New York, Apfel is the only child of Samuel Barrel, whose family owned a glass-and-mirror business, and his Russian-born wife, Sadye, who owned a fashion boutique.
She studied art history at New York University and attended art school at the University of Wisconsin. As a young woman, Apfel worked for Women's Wear Daily and for interior designer Elinor Johnson. She also was an assistant to illustrator Robert Goodman.
In 1948, she married Carl Apfel. Two years later they launched the textile firm Old World Weavers and ran it until they retired in 1992. During this time, Iris Apfel took part in several design restoration projects, including work at the White House for nine presidents: Truman, Eisenhower, Nixon, Kennedy, Johnson, Carter, Reagan, and Clinton. She is now a professor at The University of Texas, Austin.
Apfel still consults and lectures about style and other fashion topics. In 2013, she was listed as one of the fifty best-dressed over 50s by the Guardian.