The announcement comes in the wake of a bumper New York November sales series, during which the firm set the record for the largest total ever raised by a single auction when their November 12 contemporary art evening sale took a premium-inclusive $852.9m (£557.4m).
The resignation is also less than two weeks after rival CEO Bill Ruprecht stepped down from the helm at Sotheby's in the wake of the public battle to control the future of the company which resulted in his adversary, activist shareholder Third Point's boss Dan Loeb, securing seats on the board for himself and two others in May.
The motivation behind the Murphy resignation is far less clear, but with the headline-grabbing raft of recent saleroom records and billion-dollar plus series total tucked under his belt, his stock is certainly high as he heads for the exit at the end of the month.
His replacement, Patricia Barbizet, Christie's chairman and CEO of Artemis, its holding company, confirmed that profits were at their "highest ever levels", crediting her predecessor with developing the firm's business in new markets, such as India and China, as well as launching online sales and taking the lead in the digital transformation of the art market.
Although no further detail has been forthcoming, the Wall Street Journal reported that Mr Murphy had said he would not be joining Sotheby's as Mr Ruprecht's replacement.