Former sister-in-law of Mark Rosenberg and Paula Weinstein.
Earned a B.S. degree from the School of Speech (now the School of Communications) at Northwestern University (Evanston, Illinois).
Daughter of Hugh Helgenberger, who was a meat inspector, and Kay Helgenberger, who was a nurse. Marg originally wanted to be a nurse like her mother.
Has a son: Hugh Howard Rosenberg; born Oct 21, 1990 and named after Marg's father, who died in 1986 of complications from Multiple Sclerosis.
Her hometown of North Bend, Nebraska named a local street after her called Helgenberger Avenue.