Nikki Bradley, who is a disability advocate from Co Donegal, has been appointed to the Seanad by Taoiseach Simon Harris.
Senator Bradley, who lives in Milford, replaces Regina Doherty, who was elected to the European Parliament for the Dublin constituency last month.
Diagnosed with a rare form of bone cancer at 16, Ms Bradley set up an awareness campaign called 'Fighting Fit For Ewing's' (FFFE) in 2013 after receiving news that she would remain on crutches permanently.
Mr Harris said he is honoured to have appointed Ms Bradley to the Seanad.
The Taoiseach described her as a powerful voice for empowerment and he believes the new senator will make a real difference in the upper house of the Oireachtas.
Ms Bradley said her new role will hopefully enable her to deliver real change for people who have lived with disability.
The Taoiseach added that her presence in the Seanad is important for the northwest region.
