He subsequently contested the Beaufort parliamentary seat in 2013 general election on the Sarawak's State Reform Party (STAR)'s Sabah chapter ticket.

[4] He was also chosen by PN, the new federal ruling coalition led by Muhyiddin Yassin, the STAR party he belong was part of to be a senator on 16 December 2020.

[2][3] His appointment, despite the lack of credentials, had even attracted many attentions including former Prime Minister Mahathir Mohamad who has sarcastically commended it in jest.

[6][7] After more than four months of his appointment, Guan Dee was finally dropped on 27 August 2021 from the federal administration under the ruling coalition new functional Prime Minister Ismail Sabri Yaakob following Muhyiddin's resignation due to his loss of the government's majority.

[8][9] On the evening of 26 October 2021, at 4.45 pm, Guan Dee died at the age of 67, after being admitted to Hospital Kuala Lumpur due to COVID-19 complications earlier that morning.