The deal, signed last week with the TUC-affiliated Independent Union of Halifax Staff, pledges no compulsory redundancies when the Halifax converts to a public company soon.
It also gives recognition and collective bargaining rights, taking white- collar staff into the trade union mainstream.
Ged Nichols, general secretary of the IUHS, said: "This agreement defies current City wisdom that mergers and conversion to a public company means job losses. We have been given assurances that stand that philosophy on its head."
Staff working at the Halifax's 1,050 branches are covered by the deal, the first to extend job security guarantees from blue-collar employment. They earn between pounds 9,000 and pounds 50,000 a year.
The agreement commits union and management to develop pay and employment policies "appropriate to the aspiration of Halifax plc to be a world-class organisation". Mr Nichols added: "Our concern has been to ensure that the staff move forward with the business. This is the best way to promote our members' futures."
Tens of thousands of jobs have been lost in the financial services sector in recent years, so the Halifax move cuts across the "delayering" trend. It also comes as the TUC embarks on a pounds 1m campaign to put employment and job rights at the top of the political agenda .
Pressure to take stronger action on jobs will intensify on both main parties when the Council of Churches for Britain and Ireland publishes a controversial report on unemployment and the future of work.
The 300-page report, due out on 8 April, will be heavily critical of John Major's record in government. But it will also challenge Labour to do more, arguing that a Blair administration must provide "enough good work for everyone."Reuse content