Eleri Foley, two, spent months in hospital, suffering several false alarms.
She had been diagnosed with biliary atresia, where the bile ducts are blocked, at just nine weeks.
An operation to fix it failed, so a transplant was the only option.
She went to hospital just before last Christmas, devastating brother Harri, three.
Donor organs became available, but then fell through three times before docs decided on an adult liver which would then be cut to fit.
Mum Beckie, 33, said: “She was too poorly to wait any longer so it was getting desperate.”
The complex op took place in February, and after several infections Eleri was allowed home in April to Rhondda, South Wales.
Harri is now looking forward to Christmas with his sis after last year’s was cancelled.
Beckie, married to Andrew, 35, said: “They are incredibly close and it’s all he wanted.
“He was devastated Eleri was in hospital last year.
“He made us four snowmen as it was the closest he could get to our family being together.”
Beckie, backed by the Children’s Liver Disease Foundation, added: “Eleri had to learn to walk all over again. Now she’s running all over the place.”