After Rebecca completed her formal education, her father invited her on a trip to Philadelphia to visit relatives. On this trip, she met a Dr. Lukens. Born in 1786, Charles Lloyd Lukens, M.D., was a descendant of the first German immigrants to settle in America. They arrived on the Concord in 1683 and settled in Philadelphia’s Germantown. Dr. Lukens was introduced to Rebecca, and the two quickly fell in love. On March 25, 1813, at Fallowfield Meeting House, Dr. Charles Lukens & Rebecca Webb Pennock were married. Charles was 27 and Rebecca was 19.

After the wedding, Charles left Philadelphia and his medical practice and joined his father-in-law, Isaac, in the iron business at the Federal Slitting Mill. Rebecca and Charles settled near Rebecca’s family and had their first child, Martha, and a year later their second child, Elizabeth. Charles' decision to join the iron business would turn out to be a lucrative one.