Born 20 July, about 1256 (aged 39 in 1295), he was the son and heir of Nicholas de Segrave, 1st Baron Segrave, and his wife Maud, daughter of Geoffrey de Lucy, Knt., of Newington, Kent, Cublington, Buckinghamshire, Dallington and Slapton, Northamptonshire, etc., by his wife, Nichole.

On 14 January 1297 Segrave was one of the magnates attending the Hilarytide parliament at York, with the intention of proceeding against the Scots, but the expedition was postponed.

[2] Segrave, however, on 28 December 1297 received letters of protection for himself and his followers, on their proceeding to Scotland on the king's service, and he subsequently fought in the Falkirk campaign.

In 1301 Segrave attended the parliament at Lincoln and was one of the signatories of the letter of the barons to the pope, dated 12 February.

[2] On the first Sunday in Lent 1303 Segrave, with his followers dispersed, was suddenly attacked when near Edinburgh by some Scots in ambush, severely wounded, and taken prisoner with twenty other knights.

He was present at the siege of Stirling Castle, which surrendered on 24 July 1304, and, on the departure of Edward, was appointed justice and captain in Scotland south of the River Forth.

[2] Serious resistance to Edward now seemed over, and Segrave's main business was to administer the conquered districts and to track down William Wallace, who still held out.

Next summer Wallace was handed over to Segrave, by John de Menteith, and would personally escort his prisoner to London, reaching the city on 22 August 1305.

After Wallace's death, Segrave took his quartered remains back to Scotland to be displayed at Newcastle, Berwick, Stirling and Perth.

Scotland was now rapidly falling into the hands of Robert Bruce, Segrave's work was mostly preserve the English frontier: he is, in fact, described by a border chronicler as warden of the marches on the side of Berwick.

He was one of the continual council, appointed at the reconciliation between Edward II and Thomas, 2nd Earl of Lancaster in 1318, to be perpetually about the king.

His father's estates were nearly confined to the central midland counties, but he also acquired territory in Norfolk, Oxfordshire, Huntingdonshire and other shires.

In 1301 he had licence to crenellate his house at Bretby, Derbyshire, and in 1306 to fortify his manor-house at Caludon, Warwickshire, with a moat and embattelled wall.

He served in Edward III's French wars, and married Margaret, daughter and heiress of Thomas of Brotherton, Earl of Norfolk.