On 25 October 1388, he was appointed, with others, to survey the fortifications on the Scottish border, and on 24 May 1389 was made keeper for life of the royal forests north of the Trent.

[6] In 1397 Neville supported King Richard's proceedings against Thomas of Woodstock and the Lords Appellant, and by way of reward was created Earl of Westmorland on 29 September of that year.

His first wife, Margaret Stafford, had died on 9 June 1396, and Neville's second marriage to Joan Beaufort before 29 November 1396 made him the son-in-law of King Richard's uncle, John of Gaunt, 1st Duke of Lancaster.

[8] According to Tuck, Westmorland had little influence on the Scottish borders in the first years of Henry IV's reign, where the wardenships of the marches were monopolised by the Percys, leading to a growing rivalry between the two families.

The earl speedily gathered an army, defeated a force of Percy allies at Topcliffe, and then marched towards York with Henry IV's son, John of Lancaster, to confront a force of some 8000 men gathered on Shipton Moor under the leadership of Archbishop Richard Scrope, Thomas de Mowbray, 4th Earl of Norfolk, and Scrope's nephew, Sir William Plumpton.

His estates were subsequently forfeited to the crown, and Ralph, earl of Westmorland, as a reward for his quelling of the 1405 rebellion without significant bloodshed, received a large grant of former Percy lands in Cumberland and Northumberland in June 1405.

On 1 November 1410 Westmorland was granted licence to found a college for a master, six clerks, six "decayed gentlemen" and others at Staindrop, towards the completion of which he left a bequest in his will.

[14] By Margaret Stafford he had two sons and six daughters: Neville married secondly, before 29 November 1396, at Château de Beaufort, Maine-et-Loire, Anjou, France, to Joan Beaufort, the widow of Robert Ferrers, 2nd Baron Ferrers (1373–1396),[21] and the legitimated daughter of John of Gaunt, 1st Duke of Lancaster (3rd son of King Edward III), by his mistress (and later third wife) Katherine Swynford.

[25] However, in Henry V Westmorland is unhistorically alleged to have resisted the arguments made in favour of war with France by Archbishop Chichele in the Parliament which began at Leicester on 30 April 1414.

In addition, Westmorland's speech urging the advantages of war against Scotland rather than France is said to be adapted from a work by the Scottish historian, John Major, who was not born until half a century after the 1414 Parliament.

[12] The First Folio text of Henry V also unhistorically gives these lines to Westmorland on the eve of Agincourt: O that we now had here But one ten thousand of those men in England That do no work today.