The campaign, created by lead agency Publicis, tells a series of emotive stories that detail work undertaken by troops in the UK, as well as that in war zones such as Afghanistan.
Viewers are directed to http://tothebest.army.mod.uk, which will allow people to log messages of support.
Olympic rowing champion Sir Steve Redgrave, TV presenter Fern Britton and England rugby player Jonny Wilkinson are among the first signatories.
The Army claimed the theme was fuelled by research showing 87% of the UK public back British soldiers and wanted a way to express it.
'We aim to share the excellent work of soldiers in their many roles, as well as stories of the people whose lives they have changed,' said Brigadier Andrew Jackson, commander, Army Recruiting Group.
The campaign coincides with the fifth anniversary of the US-led invasion of Iraq and is set to court controversy with those opposed to the troops' continued presence.
Last November, the Army started a far-reaching overhaul of its recruitment strategy, in the face of a shortfall in numbers (Marketing, 27 November 2007).