[1][2] Earlier Kamarudin was a member of United Malays National Organisation (UMNO), a major component in Barisan Nasional (BN) coalition before switching to PAS in 1999.

[5] Kamarudin made his debut contesting but lost the Tumpat parliamentary constituency in 1995 general election when he was still in UMNO.

His wife Kamariah Kamarudin died on 11 November 2009 from colon cancer after receiving treatment at the Subang Jaya Medical Center (SJMC) including chemotherapy.

The body was prayed at Nurul Yaqin Mosque, SS7 Kelana Jaya and was buried at Bukit Kiara after Asar prayers.

They have four children, two sons and two daughters: Kamaruddin Jaafar married for the second time with Datin Yushazlinda Yaacob on 10 March 2011.

Kamaruddin Jaafar is seated with Datuk Seri Anwar Ibrahim when advancing the Angkatan Belia Islam Malaysia and Yayasan Anda Akademik in the Valley of the Coast near the University of Malaya.

Other ABIM leaders joining UMNO were Kamaruddin, Anuar Tahir and Mohd Nor Monutty and many others surrounded Anwar Ibrahim.