Five Gold Medals at the National School Championships in 1981-82

National Aquatics Championship at Delhi in 1982 by winning five Gold, two Silver and one Bronze

Nationals in Trivandrum, he stroked his way to seven Gold, two Silver and one Bronze

National Aquatic Championship at Ahmedabad in 1987, won seven Gold Medals but also created a national record in the 100 metres freestyle with a timing of 55.21 seconds, breaking his own record of 55.34 seconds set in the 1984 South Asian Games at Kathmandu

The ace swimmer, master free style and Arjuna Awardee of 1984, Khajan scored Silver at the 1986 Asian Games in Seoul in 200m Butterfly. That was the first time since 1951 that India won a medal at the Asiad

South Asian Federation Games (now known South Asian Games), where he won Gold Medals at Kathmandu in 1984 and seven at 2004 South Asian Games at Islamabad in 1989. He won a Bronze at the 1988 Asian Swimming Championships in Beijing and a Silver in the 100 metre butterfly at the world Police Games in 1988

Khajan represented India in the 12th Commonwealth Games at Brisbane in 1982, IXth Asian Games at Delhi in 1982, 2nd Asian Swimming Championship at Seoul in 1984, friendly International Game at Moscow in 1984

Khajan Singh even took part in the 1988 Olympic at Seoul

Sports officer in his early career, he presently D.I.G. with the Central Reserve Police Force (CRPF).