Jojo was born just over three weeks ago, along with her brother Balu, the Stukenbrock safari park near Paderborn said in a statement.
The keepers were delighted at yet another success in the park's white lion breeding programme.
But Jojo's umbilical cord had not been severed cleanly, and it looked like she was developing an infection, calling for vet treatment every day.
Mother lion Nala would not tolerate such intrusion, “So I took the little one home with me,” said Jeanette Wurms, the 36-year-old lion keeper at the park.
It was there that her dog Lejon, a name which is actually Swedish for lion, took a liking to the little big cat.
“Lejon looked after her with me from the first day, licking her clean, and lying next to her when I was giving Jojo her bottle. Since then we have become a very special family,” said Wurms.
Jojo's eyes have now opened and although she is still a little wobbly on her legs, she spends an increasing amount of the day running around in the garden – with her ersatz daddy dog.