His wife Kamariah Kamarudin died on 11 November 2009 for colon cancer after receiving treatment at the Subang Jaya Medical Center including chemotherapy. At that time, Kamaruddin Jaafar was in Qatar. 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:
Nur Adilah
Saiful Adli
Shahid Adli
Nur Shifa
Kamaruddin Jaafar married for the second time with Datin Yushazlinda Yaacob on 10 March 2011. The wedding ceremony was held at Tengku Kelana Jaya Mosque Petra, Kelana Jaya, Selangor. His wife is from Melaka. Also present were Mahfuz Omar, Dr Dzulkefly Ahmad and Dr Mohd Hatta Ramli.
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. While Anwar Ibrahim joined UMNO and became the Minister and Deputy Prime Minister of Malaysia, he was among the main leaders of ABIM who put their trust in UMNO with the intention of giving UMNO a deeper perspective. It was here that he was appointed chairman of the Institute of Policy Studies, a think tank founded by Datuk Seri Anwar Ibrahim. Other ABIM leaders joining UMNO were Kamaruddin, Anuar Tahir and Mohd Nor Monutty and many others surrounded Anwar Ibrahim. Anwar Ibrahim, surrounded by the people of ABIM, is disliked by the ranks of UMNO leaders such as Sanusi Junid. In 1995 he contested in Tumpat on BN/UMNO tickets but lost to a PAS candidate.
ISA Detention
On 22 September 1998, he and 12 other leaders were detained under the Internal Security Act Section 73. The detainee was
Abdul Manan, President of the Islamic Student Association of Malaysia
Prof. Dr. Sidek Baba, UIAM
Dismissed from UMNO and joined PAS
On 6 July 1999, the UMNO Supreme Council fired nine party members, including Tumpat Umno division chief Datuk Kamaruddin Jaafar, for involvement in assisting and joining opposition parties following the dismissal of his ABIM partner, Anwar Ibrahim. Deputy Prime Minister of Malaysia and UMNO vice-president Datuk Seri Abdullah Ahmad Badawi sent a show cause letter to them. Also dismissed were Ismail Yusof, Haji Said Othman, Tarmizi Ismail and Jumri Sabran from Umno Bukit Gantang. Abdullah Badawi, Senator Hamzah Mohd Zain and Saufi Daud and Mohamad Noor. On 21 July 1999, he declared to join PAS Tumpat during a talk by PAS President and PAS Spiritual Leader Dato' Nik Abdul Aziz Nik Mat. To him, there is no room in UMNO to implement the political way of Islam.
Joining PKR
On 11 September 2015, Kamaruddin with Tan Sri Muhammad Muhammad Taib has left PAS and joined PKR. During the internal upheavals of PAS in 2015, he was seen closely with PAS split-off group Gerakan Harapan Baru, which later formed the National Trust Party. Both figures say that their participation in PKR is aimed at strengthening the new coalition of the opposition and at the same time staying with AMANAH.