geer was an actor prominent in lefty/commie causes and productions, who gave financial support to a down-and-out guthrie. he acted in nyc and california in the 30s and 40s. he didn't sing so far as i know; he is on a folkways record of guthrie's, reading selections of guthrie prose preceding the songs. a recent history of the folk revival (2003 i think) says he was instrumental in getting guthrie his nyc early tv work, the same job i think where he had to dress up in comic clothes in order to sing and which he quit in disgust (this is mentioned i believe at the end of bound for glory).
this is from memory and may not all be correct.