Letterkenny solicitor Dessie Shiels will have to pay Donegal County Council's legal bill for his unsuccessful case against the local authority.
The High Court action against Donegal County Council was over the co-option of Michael McBride to replace Senator Jimmy Harte. It was dismissed in November.
Dessie Sheils brought forward the challenge on the basis that Jimmy Harte's post should have been filled by a non-party candidate.
The Labour Party insists that Councillor McBride was not a member of any party when he was co-opted.
In High Court Ms Justice Elizabeth Dunne ruled that it was impossible to reach the conclusion that Cllr McBride was either a member or candidate of the Labour Party at the time of his co-option.
Councillor Michael McBride said he was delighted the case was over: