When Lopez refused to pay the court-mandated 500 a month, his bank account was frozen, according to Rosalia Bello, a lawyer who represents his daughter, Clara.
When Lopez appealed in 2014, the Coruna court again sided with his daughter, although the monthly payment was slightly reduced to its present 400.
Bello said Clara had taken several jobs since completing her studies, but had not yet managed to find a long-term position in keeping with her studies.
"The really unprecedented thing about this case is that the support is open-ended," Bello said.
She suggested that Lopez would have to pay a stipend until his 31-year-old daughter found a well-paid job.
"There is no set rule on how long parents must support their children, but the late 20s used to mark the limit, allowing a person to get support while they studied for a degree and maybe a masters before entering the labour market," said Lopez's lawyer.
Bello said there had been several similar Spanish court decisions in recent months involving parents and children who were 30 years old or more.
"It is the [financial] crisis that has led to this change," she added.
A father in Cadiz was last year ordered to keep up a monthly payment of 500 to his 29-year-old daughter, despite the judge agreeing that she was "clearly taking a while" to finish her degree in psychology.
In the judge's consideration of the father's ability to support his daughter, he took into account the fact that he owned several cars, including a BMW, which "suggested a certain absence of financial constraints".