Chief Justiciar of England From June 1215 till July 1232 ; 1st Earl of Kent 1227; Seneschal de Poitou. He is listed as Counselor to King John in the Preamble to Magna Carta. In that document, in Latin, his name appears as "Huberti de Burgo senscalli Pictavie." Hubert de Burgh held the office as Governor of Ireland, but never went to Ireland. 
Hubert de Burgh was born circa 1170 to a family of minor landholders.
Hubert was the son of Alice, and for the soul of his mother Alice, who rests in the church at Walsingham, he made a grant circa 1230 of the advowson of the church of Oulton to the prior of Walsingham (BL, Cotton MS Nero E.vii, fol. 91).
Contender's for Hubert's father:
It's been incorrectly alleged that Hubert was the son of a brother of William fitz Aldhelm, steward of Henry II. Hubert de Burgh's brother, "William de Burgh has been identified with William fitzAldelm, Henry II's dapifer in Ireland, a man who seems to have had an unusual fascination for pedigree-makers, for Dugdale, on the authority of the herald Glover, describes Hubert as brother's son to William fitzAldelm, and later pedigrees trace Hubert's descent farther back through Arlotta, the Conqueror's mother, to Charlemagne." "There is no evidence to support it, and Round has shown that fitzAldelm was a Yorkshireman." The Close Roll for 1234 refers to Hubert's hereditary manors of Burgh, Beeston, Newton in Norfolk, and Sotherton in Suffolk. The Hundred Rolls assert that King John gave him Aylsham, and it was confirmed to him by charter in 1227.
"It is possible, though doubtful, that his father was the Walter whose daughter Adelina, with her son William, owed 40 marks in the pipe roll of 26 Henry II (1179/80) for recognition of their right to a knight's fee at Burgh, Norfolk."
Rye suggested that Hubert's father may have been the William de Burgh mentioned in 1199 in a lawsuit about the church of Colby near Aylsham, Johnston says the suggestion is possible, but definite proof is lacking.
John de Burgh of Norfolk married a daughter of William de Bosville and by her had a son Hubert de Burgh, who was King's Chamberlain, afterwards Earl of Kent. The register of the Cluniac priory of Castle Acre contains a copy of a charter of Hubert's confirming his ancestor's gift of Newton church to the priory in which Hubert speaks of his ancestor, William de Boseville.
Hubert was the brother of:
William de Burgh, died 1206, older brother, went to Ireland with King Henry II's youngest son John, and became lord of Connacht, William's son referred to Hubert as uncle;
Geoffrey de Burgh, died 1228, archdeacon of Norwich in 1202, bishop of Ely in 1225;
A charter dated 28 April 1200 at Portchester referred to a marriage between Hubert de Burgh (c.1170–1243), later earl of Kent and justiciar of England, and Joan De Vernon, youngest daughter of William de Vernon, earl of Devon, whose dowry was to be the the Isle of Wight and the manor of Christchurch, Hampshire, however, the agreement was cancelled after Earl William's wife had a son.
Hubert married three times:
in 1209, Beatrice de Warenne, who had succeeded to her father's barony of Wormegay, the widow of Doun Bardolf, and de Burgh was guardian of her young son, William. Beatrice died before 18 December 1214. Hubert and Beatrice had children:
John, probably born before 1212, only son according to West, knighted in 1229, Matt. Paris, Chron. Maj. iii. 190
in 1217 Hubert married King John's divorced wife, Isabella, countess of Gloucester, who was also the widow of Geoffrey fitz Peter's son and heir as earl of Essex. Isabella died a few days after the wedding ceremony, on 14 October.
at York in June 1221, Margaret, the sister of Alexander king of the Scots, with whom Hubert had:
Megotta (Margaret), predeceased her father, was married to Richard, the son of Gilbert de Clare, who was the nephew and heir of Hubert's second wife, Isabella;
By 12 June 1199 Hubert was styled chamberlain of John count of Mortain's household and on John's accession to the throne of England, Hubert was chamberlain of the royal household.
By 25 June 1215 Hubert was styled justiciar in official documents, succeeding Peter des Roche, the Poitevin bishop of Winchester.
Hubert de Burgh was named justiciar at the head of the lay barons who witnessed in 1216 the reissued Magna Carta.
In 1227, Hubert was made earl of Kent; the succession of the earldom was limited solely to the descendants of Hubert and his third wife, therefore not inheritable by Hubert’s son with his first wife Beatrice, John de Burgh. Both Annesley and Johnston believe this was because Hubert was a 'novus homo' and his children by Margaret of Scotland, because of their mother's royal blood, would be deserving of an earldom and to take their place among the great barons.
Chief Justiciar of England From June 1215 till July 1232 ; 1st Earl of Kent 1227; Seneschal de Poitou
Hubert died in May 1243 at Banstead manor, Surrey, and was buried in the Blackfriats at Westminster. His third wife, Margaret, survived him until 1259.
Royal Ancestry by Douglas Richardson Vol. IV. page 584
↑Johnston, 1935, p 418, citing Dugdale, Baronage of England (1675), i. 693, and "It would be tedious to multiply references to this pedigree." Cf. Harland, J.,
Mamecestre (Chetham Soc. 1861), i. 48; Notes and Queries, 4th series, vol. ix. 1879.
↑ 12.012.1 Annesley, Susanna, "The Countess and the Constable: An exploration of the conflict that arose between Margaret de Burgh and Bertram de Criel", Henry III Fine Rolls Project, 2015: The National Archives and King's College London, http://www.finerollshenry3.org.uk/content/month/fm-07-2008.html, accessed 21 December 2015, citing (Calendar of Charter Rolls 1226-57, p. 13).
Page 14: "The Templars had lent money to Hubert de Burgh, as it appears from an order in the close rolls of 1233. Henry III. had imprisoned Hubert but permitted the master of the Templars and Philip de Heye to an interview with him in the presence of his guards. Nothing was to be spoken of but the money which Hubert owed to the brothers of the Temple."
The word "uncertain" here refers to the birth date and marriage date that have (probably) been deduced from other information, and have not been confirmed by evidence or a reliable source. To post a person on Wikitree you have to have at least one date, and deduction is often worthwhile in the absence of better evidence.