Webster Boot was the younger son of Mr. and Mrs. Boot who was taken care of by Isolt Sayre after his parents were attacked by a Hidebehind in Massachusetts. Webster and his brother Chadwick were taught by Isolt Sayre, and eventually adopted by her and her husband James Steward. He took part in founding Ilvermony, and founded the house Wampus (Pm).
Webster was "argumentative but fiercely loyal". He and his brother Chadwick were excited to have their own magic school and thought Ilvermorny should have four houses like Hogwarts, but they decided against naming them after the four founders because Webster felt that a house named "Webster Boot" was doomed to fail (inter-house competitions were Webster's particular dream) (Pm).
With no magical government in the U.S. at the time, Webster became what would now be known as an Auror for hire. He met his wife through his work, who was a Scottish witch working at the Ministry of Magic. Their descendants stayed in Britain and were educated at Hogwarts (Pm).
Biological Sibling: Chadwick Boot
Great at duelling, as he duelled Gormlaith Gaunt expertly with his brother at the age of fourteen.
Other canon notes and references
Webster was fourteen at the attack on Ilvermorny around 1635, so must have been born around 1621.