The mood of “The Luck of Roaring Camp” is primarily lighthearted but switches into a somber register at the end of the story. Most of the tale is playful and enjoyable, as Harte subverts the Western genre by having a group of rugged outlaws become doting adoptive fathers to baby Luck. This humorous and lighthearted mood comes across in moments like the following, when the men deliberate over what to name the baby:
By the time he was a month old, the necessity of giving him a name became apparent. He had generally been known as “the Kid,” “Stumpy’s boy,” “the Cayote” (an allusion to his vocal powers), and even by Kentuck’s endearing diminutive of “the d—d little cuss.”
Here, Harte hopes to make readers laugh with his list of names for the baby, especially “the Cayote” (as it captures the men’s awareness of the baby’s “vocal powers,” or loud screaming) and “the damned little cuss,” which shows the men's humorous use of foul language.
The lighthearted mood of the story abruptly changes when the flood comes at the end of the story, destroying much of the camp and killing several characters. The story ends with the following lines, showing the somber, tragic mood:
A smile lit the eyes of the expiring Kentuck. “Dying,” he repeated, “he’s a taking me with him,—tell the boys I’ve got the Luck with me now”; and the strong man, clinging to the frail babe as a drowning man is said to cling to a straw, drifted away into the shadowy river that flows forever to the unknown sea.
There is nothing joyful about this passage. Kentuck speaks earnestly about the baby for the first time and, as he dies, the narrator mournfully notes how he was “clinging to the frail babe as a drowning man is said to cling to a straw” before drifting into “the shadowy river that flows forever to the unknown sea.” The change in mood communicates that, in the brutal conditions of the Old West, joy and safety are not a given and that luck, like storms and floods, can come and go at any time.