The Territorial Army is to be doubled in size under Government plans as defence cuts bite, with reservists given more training.
Veterans of conflicts in Iraq and Afghanistan will be encouraged to join the TA, with reports of "golden handshakes" of up to £15,000 for former soldiers.
The Government aims to integrate reservists better with regular troops and ensure that they are "prepared to deploy".
Defence Secretary Philip Hammond wants to double the TA in size to 30,000 in the coming years - and rename it the Army Reserve.
In a speech earlier, he set out proposals to boost the number of formal training days for part-time soldiers from 35 a year to 40.
As part of the shake-up, employers will be given more notice about their staff being called up.
The announcement comes as the military increases its reliance on reserves, with the regular Army being slashed by 20,000 troops to 82,000 by 2020.
Mr Hammond said: "For too long, the Reserves have been the forgotten part of our Armed Forces. Today marks the beginning of a fresh start.
"The changes I am proposing today amount to a radical shift in the role of reservists in delivering the nation's security.
"A shift which will see reservists routinely sharing responsibility for activities once the exclusive domain of regular forces.
"An exciting new proposition bringing with it new opportunities, and new challenges, for reservists, and for their employers."
The Government has pledged £1.8bn to fund the reservist project over the next 10 years but critics argue it is a policy driven by financial rather than military needs.
The former head of the Army, General Sir Mike Jackson, told Sky News: "Can 20,000 reservists on a contingency basis, when the unexpected comes round the corner, can they react with the speed of their regular counterparts? I think the answer to that is no."
The MoD knows it has to win over not only potential recruits to the TA, but their full-time employers as well.
There are proposals to create a "kitemark" type award to recognise supportive businesses and create a league of "patriotic employers".
Mr Hammond said: "We want to work with employers - building partnerships that deliver mutual benefit from reserve service.
"Many employers see very clearly the benefits that reserve training and experience bring to them: Delivering motivated, skilled, talented employees representing the values of the wider armed forces - integrity, application and commitment."
The Federation of Small Businesses (FSB) has broadly welcomed the moves.
But FSB policy chairman Mike Cherry said the Government must ensure businesses are properly compensated for the loss of an employee for a period of time.
He said: "It's not just the deployments, it's the additional training required. What happens if they have an accident on service that employers will want to be reassured of going forward?
"The bottom line is that like it or not the coffers won't stretch to a regular Army of the size we've been used to and the Government is having to put the best gloss it can on boosting reservist numbers to plug the gap."
Shadow defence secretary Jim Murphy said: "We support action to enhance the role of the Reserves, but the Government can go further to protect our reservists' patriotism.
"If more is going to be asked of reservists, ministers must provide more support. Anti-discrimination legislation, improved pre-deployment training and better mental healthcare are vital.
"At a difficult time for many companies, employers must be given the support they need when their workers serve on reserve duty.
"Crucially, reserve units must be integrated with regular forces rather than form stand alone units and civilian skills must be maximised in military contexts."