His father, who had emigrated from Russia, became a self-taught upholsterer and opened his own shop. His mother, an immigrant from Poland, was a seamstress. Arthur read voraciously at the public library across the street from his home and graduated from the University of Wisconsin.
The clothing line that she devised and he marketed for Rhea failed, but their romance blossomed. She soon divorced her husband, Ben Schultz, and he divorced his wife, Muriel Kotchever, and they married on July 5, 1957. Ms. Claiborne died on June 26, 2007, just short of their 50th anniversary.
The couple and a partner, Leonard Boxer, started Liz Claiborne Inc. in 1976 with $50,000 in savings and $200,000 raised from family members, friends and business associates. (Claiborne was her maiden name; she used Ortenberg privately.)
Mr. Ortenberg had homes in Manhattan, Fire Island and Montana. In addition to his son, he is survived by his daughter, Nancy Ortenberg; his stepson, Alexander Schultz; his sister, Gloria Farber; three grandchildren; and his partner, Cathy Horyn, who until recently was a fashion critic for The Times.