The news of Mackay's death was confirmed by Iggy Pop on the Iggy and the Stooges Facebook page.
"Steve was a classic '60s American guy, full of generosity and love for anyone he met. Every time he put his sax to his lips and honked, he lightened my road and brightened the whole world. He was a credit to his group and his generation. To know him was to love him," the post read.
Mackay first appeared on the Stooges' 1970 album Fun House, recording tracks like 'Fun House' and '1970'.