My post title has the wrong spelling, but it is how many people seem to prevail in searching out information on him in search engines like Google.
Until I began work on this post, I had never heard of Issan Dorsey. The Wikipedia article linked to indicates that he was born as Tommy Dorsey, Jr. in 1933, and only assumed the name Issan Dorsey in the final year or so of his life (he died in 1990 at the age of 57). He had become a Buddhist sometime in the 1960s while I assume he was in his 30s, and the name-change when he was around 58 was a reflection of this.
Apart from reading a book about him called Street Zen: The Life and Work of Issan Dorsey (written by David Schneider), you can get a fairly good idea of the man by reading this article (evidently published in 1998) titled The Lone Mountain Path: The Example of Issan Dorsey. Another account of him was published in The New Yorker on June 13, 1988: Issan Dorsey by Katy Butler.
The Website of the Hartford Street Zen Center also profiles him.
I wondered what he must have looked like as a young man, particularly when he was in his drag phase, and located these photos:
In closing, I read something quite curious. It was apparently written well before the woman who is now Joan Halifax Roshi had become the Abbot of Upaya Institute and Zen Center. The brief document by Joan Halifax is undated, and the prose hardly suggestive of anyone who aspires to one day be an author: ON ISSAN DORSEY. But if you will refer to it — it is little more than a page in length — you will find mention of Issan Dorsey’s ashes. I do not know if this state concerning them was to prove permanent, or if the situation was corrected. If I have made you curious, I am afraid that you are going to have to refer to the document to see what it is that I am speaking of.