Besides DPMM, Shah Razen has also played for AH United, non-league Viva Rangers, Wijaya FC, as well as a short trial with Indian club Sporting Clube de Goa. He was also Brunei's top scorer in the 2006-07 Malaysia Super League with 21 goals, back when DPMM were playing in the Malaysian Premier League. When DPMM joined the S.League starting in 2009, Shah Razen helped the club to win the Singapore League Cup twice, in 2009 and 2012. He was used sparingly by Steve Kean in the 2014 campaign, only starting two games and notching two goals as the team won the League Cup for the third time and only missing out on the S.League title in the final round of fixtures. In the 2014close season, he was poised to join Perak FA, which would have linked him up with former manager Vjeran Simunić who was then the Perak FA manager. The move did not materialise.
International career
After turning out for the host nation in the 2005 Hassanal Bolkiah Trophy with the Under-21s, Shah Razen's first involvement with Skuad Tebuan came in 2008, when the team was represented by his club DPMM for the 2008 AFF Suzuki Cup qualification in Cambodia. He scored 17 minutes into his debut against the Philippines on 19 October, followed by a brace against Timor-Leste two days later. However, Brunei failed to qualify for the tournament proper. Shah Razen prominently featured over the next three qualifying campaigns in 2012, 2014 and 2016. He scored a penalty in a 4–0 win over Timor-Leste at the 2016 AFC Solidarity Cup held in Kuching, Malaysia. He also opened the scoring in the competition's semi-final stage against Macau but the game eventually finished 1–1. Despite putting away his spot-kick, Brunei crashed out 4–3 in penalties. He scored two goals and became the leading goalscorer for Brunei in the 3-2 loss against Laos in the resulting third-place play-off. At the conclusion of the inaugural tournament, he was awarded the tournament's top scorer with four goals and one assist to his name. In September 2018, Shah Razen was selected for the two-legged 2018 AFF Suzuki Cup qualifying matches against Timor-Leste. He started both games as Brunei failed to advance to the competition proper, losing 2-3 on aggregate. The following year, Shah Razen accepted another national team callup for the 2022 World Cup qualification matches against Mongolia to be held home and away in June. He was played in central midfield by Robbie Servais for both matches. Despite his and the team's collective efforts, the Wasps were eliminated from the 2022 World Cup and also the 2023 AFC Asian Cup by virtue of a 2-3 aggregate loss.
