In the spring of 1598 Herbert seems to have settled in London. In August 1599 he announced that he meant to 'follow the camp' at the annual musters, and he appears to have attended her majesty with two hundred horse, 'swaggering it among the men of war' (Sydney Papers, ii. 43, 113, 115). Although handsome and accomplished, Herbert was no model courtier; he was constant in his attendance, but pursued the queen's favour in a 'cold and weak manner.' 'There [was] a want of spirit laid to his charge, and that he [was] a melancholy young man' (ib. p. 122); but he was from the first 'exceedingly beloved of all men' (ib. p. 143). The illness of his father recalled him to Wilton in September 1599, but when again in London in November Elizabeth began to notice him, and he had an hour's private audience with her (ib. p. 144). The rest of the winter he spent in the country, suffering from ill-health. He complained of a continual pain in his head, and found 'no manner of ease but by taking of tobacco' (ib. p. 165). In December another match for him was suggested with Anne, daughter of Lord Hertford. On 22 March 1599-1600, Whyte, the confidential correspondent of his uncle, Sir Robert Sidney, wrote of his return to court, where Whyte anticipated that he would yet prove a great man (ib. p. 182). On 16 June 1600 he took part in the festivities at Blackfriars, graced by the queen's presence, to celebrate the wedding of Lord Herbert, the Earl of Worcester's son, and Anne Russell, a maid of honour. At. the end of the month he expressed an intention of volunteering for military service in the Low Countries (Chamberlain, Letters, p. 82). In September and October 1600 he was vigorously practising at Greenwich for a court tournament. On the death of his father on 19 Jan. 1600-1 he succeeded to the earldom of Pembroke.
'I don't find any disposition at all in this gallant young lord to marry,' wrote Whyte on 16 Aug. 1600, but Whyte allowed that he was 'well thought of, and was keeping company with the best and gravest' courtiers. Herbert, however, was to some extent deceiving his friends. All his life he was 'immoderately given up to women,' and indulged himself in 'pleasures of all kinds, almost in all excesses' (Clarendon, History, i. 72). Before his father's death he had formed an illicit connection with Mary Fitton [q. v.], a lady of the court, who was in high favour with the queen. Very soon after Herbert had become earl of Pembroke, the lady was proved with child. Elizabeth treated the scandal very seriously. Pembroke was examined and admitted his responsibility, but renounced 'all marriage.' In March 1601 a boy was born, but died soon after birth. Pembroke was committed to the Fleet prison, and although released apparently within a month, he was banished the court. On 29 June he begged Cecil to obtain permission for him to 'go abroad to follow mine own business,' and declared that exclusion from the queen's favour and presence was 'hell' to him. On 13 Aug. he renewed his request to Cecil; 'the change of climate may purge me of melancholy, for els I shall never be fitt for any civil society.' An endeavour to obtain for himself the post held by his father of keeper of the Forest of Dean failed; he felt the indignity keenly, and was more desirous than before 'to wipe out the memory of his disgraces' by a long foreign tour. Although his father's death gave him a large fortune, he was at the time involved in pecuniary difficulties due to his personal extravagance. At the end of 1602 he was spending 'a royal Christmas' with Sir John Harington and a distinguished company at Exton, Rutland (Chamberlain, Letters, p. 171: Sydney Papers, ii. 262). In 1603 his mother conjured him, 'as he valued her blessing, to employ his own credit and that of his friends to ensure' the pardon of Raleigh. On 4 Nov. 1604 he married Lady Mary, the wealthy daughter of Gilbert Talbot, seventh earl of Shrewsbury (Lodge, Illustrations, iii. 56, 83). The wedding was celebrated by a tournament at Wilton (Aubrey).
Pembroke shared the literary tastes of his mother and uncle, Sir Philip Sidney. He wrote verse himself, and was, according to Aubrey, 'the greatest Mæcenas to learned men of any peer of his time or since.' Donne was an intimate friend. He was always well disposed to his old tutor Daniel and to his kinsman George Herbert [q. v.] William Browne lived with him in Wilton House. He was generous to Massinger the dramatist, son of his father's steward. Ben Jonson addressed an eulogistic epigram to him in his collection of epigrams, which is itself dedicated to him. Every New-year's day Pembroke sent Jonson 20l. to buy books (Conversations with Drummond, pp. 22, 25). Inigo Jones, who is said to have visited Italy at his expense, was in his service. Chapman inscribed a sonnet to him at the close of his translation of the 'Iliad,' and Davison's 'Poetical Rhapsody' (1601) is dedicated to him. The numerous books in which a like compliment is paid him, often in conjunction with his brother Philip, amply attest, the largeness of his patronage. The two Herberts, William and Philip, are 'the incomparable pair of brethren' to whom the first folio of Shakespeare's works is dedicated