Brad Drewett, executive chairman and president of the men's ATP Tour since 2012, died aged 54 on Friday from Motor Neurone Disease, the ATP said in a statement.
"Our thoughts are with Brad's family on this extremely sad day for them, the ATP and the entire international tennis community. He will be sorely missed by all," the statement read.
The Australian former professional, who reached a career-high ranking of 34, was appointed in January 2012 and helped oversee a rise in prize money at grand slam tournaments and a streamlining of the men's calendar.
Drewett announced in January that he intended to step down due to his battle with the neurological disease.
He died at his home in Sydney.