He lived in New York City from the late 1940s until 1972, during which time he was often found on Sixth Avenue, between 52nd and 55th Streets, selling records, composing, and performing poetry.

He briefly appeared in a cloak and horned helmet during the 1960s and was hence recognized as "the Viking of Sixth Avenue" by passersby and residents who were not aware of his musical career.

At one point, his father took him to an Arapaho Sun Dance where he sat on the lap of Chief Yellow Calf and played a tom-tom made from buffalo skin.

[5] After learning the principles of music in several schools for blind young men across middle America, he taught himself the skills of ear training and composition.

[4] He was rarely if ever homeless, and maintained an apartment in upper Manhattan and had a country retreat in Candor, New York, to which he moved full-time in 1972.

Already bearded and long-haired, he added a Viking-style horned helmet to avoid the occasional comparisons of his appearance with that of Christ or a monk,[10] as he had rejected Christianity in his late teens.

[9] In 1949, he traveled to a Blackfoot Sun Dance in Idaho[1] where he performed on percussion and flute, returning to the Native American music he had first come in contact with as a child.

It was this Native music, along with contemporary jazz and classical, mixed with the ambient sounds from his environment (city traffic, ocean waves, babies crying, etc.)

[4] Moondog believed he would not have won the case had it not been for the help of musicians such as Benny Goodman and Arturo Toscanini, who testified that he was a serious composer.

Glam rock musician Marc Bolan and T. Rex referenced him in the song "Rabbit Fighter" with the line "Moondog's just a prophet to the end...".

The English pop group Prefab Sprout included the song "Moondog" on their album Jordan: The Comeback released in 1990.

Big Brother and the Holding Company featuring Janis Joplin covered his song "All Is Loneliness" on their 1967 self-titled album.

New York band The Insect Trust play a cover of Moondog's song "Be a Hobo" on their album Hoboken Saturday Night.

The track "Stamping Ground", with its preamble of Moondog reciting one of his epigrams,[19] was featured on the sampler double album Fill Your Head with Rock (CBS, 1970).

Between 1970 and 1980, a blind bearded mystic called "Moondog" appeared as the title character in a four issue series of Underground comix written and illustrated by George Metzger.

According to his daughter, June, Mary was struck by his appearance and moved by his music; Moondog was stirred by the sound of her voice.