Ngcobo was born in
Cato Manor near
Durban, South Africa, and started played amateur soccer at a young age for African Bush Rangers, Rand Koreans, Union Jacks. He later joined
Zulu Royals and
African Wanderers in the new
NPSL for blacks in 1971. In 1972, Ngcobo was recruited by Kaizer Chiefs' Ewert Nene when he scored six goals against them in a friendly match. In 1974, he won the league and the BP Top 8 and in the same season he scored a hat trick in a 7–1 win over
Moroka Swallows. He left for
Denver Dynamos in 1975 after leading Chiefs to their first ever league title the previous season with
Kaizer Motaung and
Patrick Ntsoelengoe. Motaung scored seven goals that season, providing one assist, Ntsoelengoe scored five goals and four assists and Ngcobo netted five times, while delivering six assists. The following season, Ngcobo and Ntsoelengoe both moved to Minnesota Kicks. In 1976 where he won the Benson and Hedges Trophy, Sales House Cup and the BP Top 8 he set a new record of the fastest goal scored in 10 seconds in a 3–1 win over
Moroka Swallows on 11 October 1976 in
Vosloorus. In February 1980, before being named the 1979 Footballer of Year, he scored against
Highlands Park in that famous Mainstay Cup Final replay and he scored a 13-minute hat-trick against
Moroka Swallows. He went AWOL for trials in Uruguay with
Peñarol organised by
Mario Tuani along with
Goodenough Nkomo upon returning he was fined R1000. He later played for Peñarol being striker partners with young
Venancio Ramos and
Fernando Morena. After suffering from niggling knee injuries later in his career, Valdez retired in December 1984. ==International career==