At the start of his career, Stewart was a specialist opening batsman for England, with wicketkeeping duties being retained by Jack Russell, who was generally recognised as the superior gloveman and who batted down the order. However, Russell, the inferior batsman, would often be dropped to improve the balance of the side (i.e. to accommodate an extra bowler or batsman), in which case Stewart would don the gloves. After enduring years of selection and deselection, Russell retired from international cricket in 1998, leaving Stewart unrivalled as England's keeper-batsman until his own retirement in 2003.
He was vice-captain of the England side during most of Michael Atherton's tenure as captain, eventually succeeding him in 1998. While England won their first series under him, against South Africa, failures against Australia and in the 1999 cricket World Cup saw him sacked from the captaincy to be replaced by Hussain. During his captaincy, he had the unusual distinction of simultaneously captaining the side, opening the batting and keeping wicket.
He continued as an England player for five more seasons, and became only the fourth player to score a century in his 100th Test, at Old Trafford.
In 1994 at the Kensington Oval in the West Indies he became only the 7th English batsmen to score centuries in both innings of a Test match. His highest Test score, 190, was against Pakistan in the first Edgbaston Test on 4 June 1992 - a match that was drawn. Stewart has the lowest batting average of any player to have scored 8000 or more runs in Test cricket. However, this still represents a fine return given he had the burden of keeping wicket in 82 of his 133 test matches.
As a specialist batsman in Test cricket, Stewart averaged 46.90 in 51 games with 9 centuries. As wicketkeeper batsman he averaged an impressive 34.92 from 82 tests, higher than many of his contemporaries and many of the current batch of international wicketkeepers. He was unlucky enough to be on the losing side in a record 54 Test Matches.
He is also the younger son of a former English Test cricketer, Micky Stewart. Stewart is a well-known supporter of Surrey County Cricket Club and Chelsea F.C. His favourite Chelsea player when growing up was John Hollins, which is why he always wore the number 4 shirt in One Day Internationals.