He played in twelve countries across four continents: United States, Senegal, Morocco, Switzerland, Saudi Arabia, Malaysia, South Africa, Mali, Germany, Turkey, Sweden and Norway.
However, Diallo is also remembered for the incident on 16 August 2000 in a game against the MetroStars, where he collided with and stepped on Metro goalie Mike Ammann, breaking his ribs and puncturing his lung.
He had a four-goal game against the Los Angeles Galaxy in only his second match with the team, but his scoring tapered off and the Metros missed the playoffs.
Diallo moved to Saudi Arabian club Al-Ahli on 7 October 2002, but was dropped in November after failing to impress.
Diallo won 46 caps for Senegal, scoring 21 goals, in a career which saw him represent his country at the African Cup of Nations in 1994.