Urging people to back his party in the highly marginal Cardiff North constituency, he said the economy was back on track. The Conservatives won the seat by fewer than 200 votes over Labour in 2010.
Mr Hague also defended plans he drew up for English-only votes in Westminster, denounced by Labour as a “stitch-up.”
He told BBC Wales, “There are 52,000 more jobs in Wales after this period of five years of a Conservative-led government. After we’ve been through this very difficult economic period, at last this year living standards are going to be better than they were five years ago.
“So the message is don’t put all that at risk if we go back to the policies that we had before.”
As Commons Leader, Mr Hague, who has stood down as an MP, drew up plans that would mean legislation only affecting England could only be passed with the consent of English MPs.
He said his proposals also allowed for English and Welsh votes on issues affecting both nations, so “decisive votes are going to be cast by the MPs that represent England or represent Wales. Nobody is being excluded from anything,” he said