The Star Tribune newspaper, in his native Minnesota, said Bly died on Sunday.
Bly emerged from two years in the US navy in the 1940s to become a prodigious poet, translator and writer of prose.
In the 1960s, Bly became a leading opponent of the Vietnam war.
Smith said Bly’s relationship with his own father, a taciturn Norwegian farmer, “led to an examination of what it is to be a man.
“He was concerned that men were losing their inner lives, their feeling lives, their connection with stories and traditions and literature.
Bly, Rylance wrote, “had this penetrating ability to see what was going on and he didn’t have any shyness about saying it.
Referring to Bly’s extensive work as a translator, Rylance wrote: “The most profound thing that an elder man can do for a younger man is to mentor and encourage a particular gift.