Like that of his brothers, George Mansker's date and place of birth are unknown. If his father Ludwig listed the children in chronological order in his will, then George was the second born, after John and before Kasper; this would mean, if the early Tennessee legends about Kasper are true and he was born at sea, on board the ship Christian between Germany and Philadelphia in 1749, that both John and George were born in Germany.

George was raised in Clark's Valley, Pennsylvania, in what was then Lancaster County, and in early 1778 he took an oath of allegiance to the Commonwealth of Pennsylvania, which required him to renounce his previous allegiance to George III and England (see the Oaths of Allegiance and Abduration).

In 1778 George also appears in the muster roll of the Lancaster County militia in Captain Jonathan McClure's Company, 4th Class, 4th Battalion. In August 1779 his name appears on rosters of the 7th and 8th Classes which had been sent to Northumberland County, Pennsylvania, to protect settlers from marauding Native Americans, and by October 1779 he is back on the rolls of Captain McClure's company.

Sometime between 1780 and 1783, George moved south and west from Pennsylvania, eventually arriving in the Cumberland area of North Carolina (now Tennessee) to join his brother Kasper, who had settled in the area in 1779. On 14 April 1786 George was given a land grant of 640 acres by North Carolina, for the purpose of planting corn (the size of the acreage indicates that he was married at the time of the grant).

George's wife was named Elizabeth White, the same name as Kasper Mansker's wife, but a different person. They most likely married circa 1770 in Pennsylvania, and were to be the parents of at least five children: George Jr., William, Lewis, John and Mary (see Descendants Page). There is strong speculation that some of the "Missing" Manskers are also children of George and Elizabeth Mansker as well.

The Sumner County, Tennessee, Archives has on record the following stock identification mark registered to George "Mansco" in 1787: "Stock mark a crop off of the right ear & a swallow fork upperkeal [sic] in the left and the dew lap cut down." Although Kasper also had an actual cattle brand registered in addition to the ear-cropping marks, George apparently did not.

For a time, George and Kasper operated a hominy mill on the bank of Mansker Creek, in what is now Sumner County. However, the public records for the period of about 1790 to 1815 show that the George Mansker family moved around quite a bit. George and George Jr. appear on the tax lists for Logan County, Kentucky, in 1792, 1794 and 1795. Census records show that the Mansker grandchildren of George and Elizabeth were born in Kentucky and Tennessee at various times, so it may be that the family moved back and forth across the border. Logan County is just across the state line from Sumner/Davidson Counties, Tennessee.

By 1817 George and Elizabeth, along with sons George Jr. and William, have moved to Pocahontas, Lawrence County, Arkansas (an area which later, in 1835, became Randolph County). Lewis and John ended up in Missouri. The Mansker families of the Cape Girardeau area are descended from them.

George died sometime in July 1822; on the 22nd of the month a bill in the amount of $5.25 was presented to the estate by one George Shaver, who had made the coffin and seems to have also appraised George's estate.

The move from Tennessee apparently was not an especially healthy one for the Mansker men. George's death was followed in rapid succession by all four of his sons: John died in Wayne County, Missouri, in December 1822; on the 25th of the same month, George Jr. died, presumably in Wayne County, Missouri (copies of his will have been found in both Missouri and Arkansas, so his place of death can't be pinpointed with any certainty); Lewis died in Cape Girardeau, Missouri, in September 1823, and William died in Lawrence County, Arkansas, in December 1823. The causes of their deaths are not recorded, but it seems likely that they were victims of either yellow fever or cholera, both of which were epidemic in the area.