The Elkton town was known for its "quickie" marriages. Furcillo however, was already married and although he offered to take care of the child, June's mother Ethel insisted that she bring up the baby, partly so that June could pursue her dancing career.
Although Donald Furcillo claimed to be Nicholson's father and to have committed bigamy by marrying June, biographer Patrick McGilligan asserted in Jack's Life that Latvian-born Eddie King (originally Edgar A. Kirschfeld), June's manager, may be the father, and other sources have suggested that June Nicholson was unsure of who the father was. Jack's mother was of Irish, English and Dutch descent though he and his family self-identified as Irish.
Jack was brought up believing that his grandparents, John Joseph Nicholson (a department store window dresser in Manasquan, New Jersey) and Ethel May Rhoads (a hairdresser, beautician and amateur artist in Manasquan), were his parents. Nicholson only discovered that his "parents" were actually his grandparents and his sister was in fact his mother in 1974, after a journalist for Time magazine who was doing a feature on Nicholson informed him of the fact.
By this time, both his mother and grandmother had died (in 1963 and 1970, respectively). Nicholson has stated he does not know who his father is, saying "Only Ethel and June knew and they never told anybody" and has chosen not to have a DNA test or to pursue the matter.