As a boy, he moved with his family to Oregon. As a young man, he wandered and took a variety of jobs — a cook, judge, miner, Pony Express rider, and he was even jailed for stealing a horse in California. He also wrote essays, local color prose, and poetry. On a decade-long trip to London, he wore a comically-exaggerated Western outfit that included cowboy boots and spurs, a cape and sombrero. His appearance was a disgust to other American writers there like Ambrose Bierce and Mark Twain. Welcomed as an authentic curiosity nevertheless, Miller earned a greater reputation overseas than at home – the British even gave him the nickname "The Byron of Oregon."
After his death, Miller was cremated and his ashes spread at his California estate, "The Hights," now Joaquin Miller Park. The event was photographed.
From Miller's 1890 collection In Classic Shades and Other Poems, "The True Poet":
O, heard ye the eloquent song of God's silence?
The vines are His lines; and the emerald sod,
The page of His book, and the green-girdled islands
Are rocked to their rest in the cradle of God.
God's poet is silence! His song is unspoken
And yet so profound, and so loud, and so far,
That it thrills you and fills you in measures unbroken —
The unceasing song of the first morning star.
The shallow seas moan! As a child they have muttered,
And mourned, and lamented, and wept at their will;
The poems of God are too good to be uttered —
The dreadful deep seas, they are loudest when still.