 Almost immediately, however, he spent two years in national service, and finally made his league debut for Charlton at right-half against Sheffield Wednesday in January 1957, a year in which the club struggled (and ultimately failed) to avoid relegation from the First Division.After not making the first team the following season, he was named again in the squad in December, 1958 – this time at full-back, a position he played for the rest of his career.Sewell made 204 first team appearances for Charlton, scoring five goals, before signing for London rivals Crystal Palace on 25 October 1963.