"I have disappointed and failed to live up to the standard I expected of myself," Spitzer said, standing next to Silda Wall Spitzer, his wife of more than 20 years.
"I must now dedicate some time to regain the trust of my family."
Prosecutors said last week that the network operated in cities across the US and in London and Paris, employing more than 50 prostitutes who charged fees of up to $5,500 an hour.
The network even offered clients the option of paying with cash, credit card, wire transfer or money order, selling the prostitutes' services through a website that ranked each of them on a system of one to seven diamonds.
The Republican Governors Association issued a swift call for Spitzer to step down.
"Eliot Spitzer campaigned on ethics reform; unfortunately the governor of New York has egregiously failed his constituents," the group's executive director, Nick Ayers, said in a statement.
Spitzer did not answer questions on whether he would step down.