The channel has retained Firefly Communications to promote its year-long nation-wide campaign, 'A small piece of history', alongside raising awareness of the channel itself.
'A small piece of history' launched last September, centring on a competition inviting viewers to write in with stories about personal artefacts and memorabilia that they believe to be of historical interest.
Disappointing entry numbers forced the channel to bolster its PR efforts, prompting Firefly's appointment.
Firefly account director Sharon Gertler, who co-heads the project with director Mark Mellor, said: 'The channel launched the campaign last year, but hasn't been doing any external PR for it.
'It wanted to raise the number of entries to the competition and raise awareness of The History Channel itself,' he added.
Firefly is set to kick off the PR campaign with research into people's perceptions of historical events, to be published later this month.
'There's a big focus on regional press and radio,' said Gertler.
'We are going to be running a campaign looking at how much value people place on history and how much they remember about historical dates,' she added.
The four-strong Firefly team reports to History Channel head of press Jo Mitchell.
Firefly's appointment is the first time The History Channel has used agency support. Launched in 1995, the channel now reaches more than 140 million households across the world, via both satellite and cable.