Diallo started his career at Hafia in 1994 before moving to Deinze in Belgium in 1997. Diallo signed for Westerlo in 1998 before moving to Turkey in 1999 with Gaziantepspor for a season. Diallo spent two seasons with Yimpaş Yozgatspor before signing for Diyarbakırspor for a season and then moved to Azerbaijan with Shamkir. Diallo stayed at Shamkir for a season and a half before moving to Genclerbirliyi Sumqayit in 2005 where he made 50 league appearances before retiring in 2007.