In 1998, Sweeney joined Pontypridd RFC from Glyncoch RFC.
In 2003, with the introduction of regional rugby in Wales, Sweeney joined the Celtic Warriors. When the club was liquidated in the Summer of 2004 he signed for the Newport Gwent Dragons.
In the summer of 2008, after 4 seasons with the Newport Gwent Dragons Sweeney signed for the Cardiff Blues. Sweeney was told upon joining the Blues that he was signed to be used as an outside-half (his preferred position) as opposed to inside centre. This meant that Sweeney would be competing with Nicky Robinson for the number 10 jersey. He scored a try seconds after coming on in the EDF Energy Cup final against Gloucester at Twickenham on 18 April 2009.
Despite several times being linked with moves away from the capital city side, Sweeney remains at his home region. In 2012, ambitious Russian club Krasny Yar[1] moved to make him the first Welsh international to play professionally in the Russian league. The switch was derailed at the last minute by budget issues at Cardiff Blues making it impossible for them to find a satisfactory replacement for the reliable Sweeney. The Russian option remains one Sweeney is keen to explore in future.
After playing well during the six nations, Sweeney was selected in the Wales squad for the 2003 Rugby World Cup. He was on the bench for the final pool game against New Zealand and came on just after half-time to make a big impact. His hand-off on Carlos Spencer saw him break straight through the defensive line with Colin Charvis in support. After passing to Charvis, who passed back to him, he was finally brought down by Doug Howlett just 1m short of the line. The ball was quickly passed out to Shane Williams on the left wing who finished the move by scoring a try.[citation needed]
Whilst playing against South Africa in 2004, his teammate Alix Popham was knocked unconscious whilst tackling. Sweeney noticed Popham was unconscious and acted quickly to prevent Popham from swallowing his own tongue.[citation needed]
In 2007 Sweeney was selected in the Wales squad for the 2007 World Cup.[citation needed]
On 16 April 2014 he was picked in the Barbarians squad to face Clontarf. Being one of the biggest names in the squad.[citation needed]
Personal
Ceri married his wife Helen in a luxurious ceremony in South Wales. They have two children.[citation needed]