Blair McDougall will contest the seat in June’s vote.
However, he will have to convince voters to back Labour despite the fact the party’s own branch doesn’t endorse Jeremy Corbyn.
In an open letter, 14 members across Eastwood said Corbyn “cannot provide the leadership” to form a government.
They added: “We need a credible, competent opposition, but Jeremy Corbyn is currently unable to fill all positions on his front bench. Jeremy Corbyn wants to captain a ship for which he has no crew. For the good of the party and, more importantly, the country, he must step aside.”
And McDougall himself has been a regular critic of Corbyn.
During the leadership election he backed Owen Smith on the basis “we cannot win with Jeremy”.
He also described as “fantasy” a remark by Corbyn that Labour were ahead in the polls last year.
Scottish Conservative deputy leader and MSP for Eastwood Jackson Carlaw said:
“How can the Labour candidate in East Renfrewshire expect people’s votes, when members themselves won’t back Jeremy Corbyn?
“It demonstrates the chaotic state the Labour party finds itself in.
“Even Blair McDougall thinks Jeremy Corbyn can’t win, which tells voters across East Renfrewshire everything they need to know.
“Only our candidate, Paul Masterton, can beat the SNP here, as we did at last year’s election.”