Having first played as a youngster at Middlesbrough Rugby Club (with Rob Andrew and Bernie Coyne), Underwood went on to become one of the greatest wings in rugby union. Underwood is the leading try scorer for England in international matches. He first played for England in February 1984 against Ireland at Twickenham. He won 85 England and 6 Lions caps between 1984 and 1996 (then an English record, later surpassed by Jason Leonard – it remained the highest total for an English back, though that has since been overtaken by Jonny Wilkinson), scoring a record 49 tries for England, and 1 for the British Lions, making him one of the leading try scorers of all time. He played for England in the Rugby World Cups of 1987, 1991 and 1995.