Tony Blair has taken a part-time post with US investment bank JP Morgan.
Tony Blair is said to be providing "political and strategic advice"
Mr Blair, who stood down as UK prime minister in June last year, has been employed "in a senior advisory capacity", the bank said.
He said he looked forward to advising the bank on the "political and economic changes that globalisation brings".
It is not known how much JP Morgan will pay him, but some estimates say more than $1m (£500,000) a year. The bank said he had a "unique perspective".
It said Mr Blair would advise the firm's chief executive and senior management team, "drawing on his immense international experience to provide the firm with strategic advice and insight on global political issues and emerging trends".
"Our firm will benefit greatly from his knowledge and experience," it said.
Since leaving Number 10, Mr Blair has been an unpaid envoy for the Quartet of Middle East peace negotiators.
Mr Blair earlier told the Financial Times he planned to take up "a small handful" of similar roles with other companies in different sectors.
"I have always been interested in commerce and the impact of globalisation.
"Nowadays, the intersection between politics and the economy in different parts of the world, including the emerging markets, is very strong."
As an envoy for the Middle East quartet, Mr Blair works on behalf of the US, Russia, the UN and the EU.
In October, Mr Blair was publicly backed by French President Nicolas Sarkozy for the job of president of the European Council - dubbed "president of Europe" - a role which will be created under the terms of the new EU reform treaty.
However, the former prime minister has played down speculation he is to be offered the job, with his spokesman at the time saying Mr Blair is "focusing on his current role in the Middle East".
JP Morgan, one of Wall Street's leading banks, is part of JP Morgan Chase & Co, a global financial services firm with assets of $1.5 trillion (£760bn) and operations in more than 50 countries.