Timani played soccer until he attended Liahona High School and was introduced to rugby union.
He made his test debut for the Wallabies in 2011. His usual position is lock. He is the older brother of Lopeti Timani.
He moved to Australia at the age of 19 and switched codes, playing rugby league for Cronulla-Sutherland Sharks in the NRL"s Jersey Flegg competition in 2006, and in Premier League in 2007.
In August 2007, Timani returned to rugby union, playing for Perth Spirit in the Australian Rugby Championship. He was selected for all Perth Spirit matches for the season, and played 8 times as starting lock.
The following year, Timani made his Super Rugby debut for the Western Force against the Sharks on 15 February 2008 in Durban, although he only made 3 appearances for the franchise during the season. He moved to the Brumbies in 2009 and played most of the Super Rugby season, but then fell from favour and did not get any game time in 2010.
At that time, he was eligible to play for both Tonga (by birth) and Australia (by residency).
He chose Australia and was selected by the Wallabies, playing against Samoa at Stadium Australia in Sydney on 17 July 2011. His decision to play for Australia meant he became ineligible to play for Tonga and it probably cost him an appearance at the Rugby World Cup later that year. He was not selected for the Australian 2011 world cup squad but probably would have been selected for Tonga, if eligible.
In 2013, he signed a three-year deal with French side, Montpellier.
He joined the club after travelling with the Wallabies on their 2013 end-of-year tour.