The 70-year-old Spanish tenor will chair the International Federation of the Phonographic Industry (IFPI).
The music world was facing "enormous changes and challenges", he said.
He said he "passionately believed in the importance of respecting talent and in the rights of all those who perform, create, produce and invest in music".
The IFPI has been at the forefront of the campaign to counter illegal music sharing and pursuing the biggest offenders.
IFPI chief executive Frances Moore said Domingo was an artist who "speaks from the heart about the issues that matter to him".
"His forceful advocacy for the intellectual property rights of the music sector comes at a pivotal moment, as governments in many countries consider new legislation to curb piracy and help develop the legitimate digital music business," Moore added.
Opera singer Placido Domingo is taking a leading role the fight against music piracy after becoming chairman of the global body representing record labels.