Glasser was a member of the Perlo group of Soviet spies during World War II and worked closely with Harry Dexter White.
In December 1941, the Secret Service forwarded a report to Harry Dexter White indicating that it had evidence Glasser was involved in Communist activities.
After America became involved in World War II, Glasser received appointments to higher-level positions, such as Vice-Chairman of the War Production Board, was dispatched to serve as economic adviser to American forces in North Africa, U.S. Treasury representative to the United Nations Relief and Rehabilitation Administration, and Treasury representative to the Allied High Commission in Italy.
The text from KGB Archives reads in part as follows: Our agent RUBLE, drawn to work for the Soviet Union in May 1937, passed initially through the military "neighbors" and then through our station valuable information on political and economic issues.
Transcripts of Glasser's promotions and job rating forms signed by Coe, Ullmann, and White are in Interlocking Subversion in Government Departments Report.
Pavel Fitin later described as "valuable" the political and economic information Glasser passed along, all of which found its way into thirty-four special reports to Joseph Stalin and other top Kremlin leaders.
A 4 June 1945 cable reports Glasser would be on the Treasury committee advising Supreme Court Justice Robert Jackson, the U.S. prosecutor at the Nuremberg War Crimes Tribunal.