Former Tory MP and Welsh Office minister Rod Richards has joined the UK Independence Party, he has confirmed.
He said it follows "10 years of frustration watching the country I love going down the pan and the parties in charge seemingly doing nothing about it".
Mr Richards refused to say whether he will seek the party's candidacy in next year's European Parliament election.
The current UKIP MEP for Wales John Bufton is standing down in June 2014.
Mr Richards was MP for Clwyd North West between 1992 and 1997 and was leader of the Tories in the Welsh assembly.
He told BBC Radio Wales he joined UKIP after becoming disillusioned with the way the mainstream parties were running the country.
"I found more and more I was complaining about it and not doing something about it," he told BBC Radio Wales.
"I feel I have to get up and do something. I will give it my best shot."
He said he believes the UK's membership of the European Union (EU) was "holding us back" and was preventing the country trading with countries such as China and India.
He also claimed that as well as all the "red tape and restrictions", the UK paid "far more into the EU than we receive" and that Welsh businesses were suffering.
But Mr Richards would not be drawn on whether he wanted to seek UKIP's candidacy in the 2014 European Parliament election.
"I'm a new lad on the block," he said.
"I'm getting to know my new friends in UKIP."
He said the matter of candidates was a matter for the party, adding that it was an issue that would be kept confidential within the party.
"I'm certainly not someone who will only be putting a cross in the box," he added.
"I shall be an active member."
Mr Richards' decision to join UKIP is the latest twist in an eventful political career.
In 1996 he was forced to quit his ministerial post in John Major's government over allegations about his private life and did not fight the 1997 General Election.
Elected to the Welsh assembly in 1999 as Conservative group leader, he stepped down a few months later after being accused of assaulting a young woman.
Subsequently cleared of assault, Mr Richards later admitted to problems of alcoholism and resigned as an AM in 2002.
In 2008 he was cautioned by police after being arrested over an alleged assault on a Conservative party worker, later describing the incident as a "clip around the ear".
On Monday it emerged UKIP Vale of Glamorgan councillor Kevin Mahoney had withdrawn from the selection process to be the party's European candidate in Wales in protest at Mr Richards joining UKIP.
"If he did apply to be a candidate at any level, whether it be general election, European election, or even quite frankly local authority level, I personally wouldn't want to be associated with Mr Richards and I would strongly oppose his candidacy on any level within UKIP," said Mr Mahoney.
"I have have already stepped out of the MEP selection process in order that I'm able, as a non-candidate, to pass opinion on the calibre and motives of any candidates that put themselves forward for selection."
Mr Mahoney said he had also resigned as UKIP's regional organiser for Wales, but stressed that was "an internal party matter" on which he would not comment further.