in february 1989, singh was appointed foreign secretary of india. he held the personal rank of grade-i ambassador, the highest in the indian foreign service. prior to becoming foreign secretary, he was india's longest serving ambassador to pakistan from 1985 until 1989. he also served as ambassador to austria from 1982–1985, additional foreign secretary from 1979–1982, ambassador to afghanistan from 1977–1979 and ambassador concurrently to jordan, lebanon and cyprus from 1974–1977. he was the longest-serving official spokesman of the government of india from 1969–74. in 1968–69 he served in the ministry of commerce as director foreign trade.