Kirkman grew up in Greenville, South Carolina, in a military family who moved about regularly.
In a 2015 interview with Cynthia Dagnal-Myron for The HuffPost, Kirkman described his hometown as a place where "the Civil War never ended." He encountered bigotry and intolerance. "I was an alien to this world," he said. "And was treated like one. Bullied. Humiliated. But I was determined to write my way to a better life. I would write my way to freedom."
He spent part of his youth living on the slopes of an active volcano in Sicily, where a beloved teacher, Signora Longo, told him how St. Agatha used breast milk to protect Catania from the volcano's destructive flows.
A gifted child, Isaac painted and drew, eventually gaining admission to the Joe Kubert School of Cartoon and Graphic Art in New Jersey.
He also spent long years in the American hospital system, where he was diagnosed with Ehlers-Danlos Syndrome, a hellish genetic condition that causes progressive deterioration of connective tissues throughout the body and intractable pain. He also struggled with depression throughout his life.
A decline in health prompted him to turn his focus to writing. "There remain obstacles," he said. "But I will make art from them."
Possessing an open and inquisitive mind, he pored over psychology and occult texts.
A troubled teen, for a time he lived on the streets. "I always had a notebook on me," he said. "Writing on the couch as my friends sold drugs out the front door, sleeping outside, writing descriptions of the junkies and the outlaws, writing metaphors to capture the agony of the ghetto, and the ecstasy of God."
He found his heart and words—depicting the human struggle towards redemption—on the streets.
After moving to Tucson, Isaac would often walk the streets, whether in scorching heat or torrential rains. He'd leave votive candles on shrines and the sites of recent homicides,. "to pay respect to the spirits and religions of the barrios, honoring their losses as well as my own," he said.
In Barrio Santa Rosa, where he lived, he got on the path to sobriety and enrolled in his first and only writing class at The Writers Studio. Soon afterwards he had his first piece of fiction published.
"I never gave up on writing because it was my destiny," he said. "Because I had to tell the stories of the forgotten. I didn't come to this through academics. I came from my own grave. I have been beaten humble and beaten pure."
Isaac's poetry and prose have appeared in numerous journals: Waxwing, Huffington Post, Thuglit, Tucson Weekly and many others.
He served as a board member for the Tucson Poetry Festival, Words on the Avenue and co-founded The Reading Series, a literary event that now exists as part of his legacy.
He was a poet, writer, mystic, activist and a soul not of this world.
Isaac once said of Ehlers-Danlos Syndrome: "It is an aspect of me, but it does not define me. I view it as spiritual lesson from my creator to strengthen my spirituality, gratitude, and empathy through pain. I don't ever feel like I am really in my body. I am a ghost."