Video producer Chris Slade, formerly of Phones 4U, will join the agency along with Clare Rutherford as new business executive, who joins from Wowcher.
Faaizah Ali has also joined the agency from the Greater Manchester Police as PR & marketing executive.
The new hires follow the appointment of Dan Laurence to the role of managing director at the Manchester-based agency last month.
Laurence said: "Chris, Clare and Faaizah are three fantastic additions to support key areas of our business. I’m delighted to welcome them to HGA and look forward to working alongside them all to provide an exceptional service to our clients. We have some really exciting projects lined up over the months ahead and these appointments confirm our ambition to attract the best talent in the region to HGA."
In August, HGA told C&IT that is was forecasting 20% revenue growth in 2014 as it enters new areas of the events market.
HGA Creative experienced record-breaking sales of £2.5m for its financial year to 1 June 2014.