The younger brother of Saeed Ahmed (Pakistan 1958-1973), Younis made his first-class debut at the age of 14 for the Pakistan Education Board against South Zone in March 1962.

Younis arrived in England in April 1965 to begin playing cricket for Surrey. He played his first first-class match for the county two months later against a South Africa touring party and made his County Championship debut in 1967. He remained with Surrey until 1978 and was a key part of the side that won the County Championship in 1971. However, he left Surrey in acrimonious circumstances after the club did not renew his contract.

After leaving The Oval Younis was signed by Worcestershire and played there for four years between 1979 and 1983. However his contract was cancelled by the county when allegations arose that Younis had placed bets for his county to lose - allegations which Younis denied. He concluded his English playing career in Glamorgan where he played alongside fellow countryman Javed Miandad.

Younis also played for South Australia during the 1972/73 season, acting as the overseas player on the recommendation of Donald Bradman.^[7] He won the Quaid-e-Azam Trophy while playing for Pakistan International Airlines in 1969, matches which were used by Younis to get used to conditions ahead of his international debut.^[8]

Younis made two Test appearances against New Zealand in 1969.^[9] However, he was banned by the Pakistan Cricket Board for participating in the DH Robins' XI tour to apartheid South Africa in late 1973. The ban was rescinded in 1979,^[10] but Younis did not return to international Test cricket until 1987.