NUA Healthcare Services is seeking 200 staff to care for people with intellectual disability and mental health issues.
The firm based in Naas, Co Kildare employs 1,600 at its 53 centres nationwide, supporting 350 clients - about 240 of whom live in the centres.
They and 110 non-resident clients receive support and therapy for their conditions.
The firm said it has no confirmed cases of Covid-19 among residential clients and is taking new applicants.
However, it said "a handful" of staff have Covid-19 "and are all following relevant protocols in terms of self-isolation".
One of its non-resident clients also contracted and has recovered from the infection.
"Nua is managing to sustain safe service delivery for its current resident population and is also accepting new placements, where appropriate, in an effort to support the overall Government strategy for dealing with Covid-19," said Eric Behan, quality and safety manager at Nua.
Unlike nursing homes, residents of Nua facilities are younger on average and often live in their own units, lowering the Covid-19 risk associated with large numbers of people in shared spaces.
Mr Behan said Nua is "prepared in the event of a residential service user testing positive", and has put in place "an intensive monitoring and management system to try to avoid such a development".
Nua said it wants to hire up to 200 more nurses, social care workers and assistant support workers in coming weeks. It has dozens of current openings listed on online job sites.
The company - which began in 2004 as a single Kildare care centre for people with Asperger syndrome - is rapidly expanding.
It has hired 300 staff in the past two years. Its organisational map identifies four sites in Cork, Tipperary and Waterford for new mental health homes. Seven new intellectual disability homes are planned in half a dozen counties, including two in Waterford.
Most of its facilities provide full-time residences with high staff-to-client ratios.
"Our services are very intensive, but our work is hugely rewarding. We offer excellent career development opportunities," said Michelle Kirwan, Nua's recruitment and retention manager.