Narrated in the first-person voice by an unnamed narrator, "Salvatore" opens with the narrator cryptically stating, "I wonder if I can do it." The narrator proceeds to tell the story of his protagonist, Salvatore, an Italian fisherman living on an unnamed Italian island, presumably Capri.
The narrator meets Salvatore when Salvatore is fifteen. The boy is carefree, spending most of his days tanning on the beach and helping in his father's vineyard. Salvatore falls in love and becomes engaged to a beautiful girl from the Grande Marina area of the island they live on.
Before he can marry, Salvatore leaves for military service in the navy under King Victor Emmanuel. He misses his home and feels nostalgic over the loss of his family home and his fiancée. His service involves him going ashore at many foreign places, including Venice, Ban, and China.
In China, Salvatore falls ill and learns he has rheumatism, a condition that makes his limbs inflamed and in pain. The illness means he is unfit for service, news that fills the homesick young man with delight. He returns home, joyful to be reunited with his loved ones. However, when he returns his fiancée is not waiting for him at the shore. That evening he goes to her home and learns that she and her family have broken the engagement because Salvatore's illness means he may not be able to work enough to provide for a wife.
Though upset, Salvatore accepts the girl's decision. He soon learns that Assunta, an older woman, has fallen in love with him. Although she is "ugly as the devil," he decides to marry her. The two marry and have two sons. The couple get along well and live in a quaint little house on a vineyard. Salvatore never speaks ill of the girl who rejected him, but Assunta says cruel things about her.
Despite his illness, Salvatore perseveres and continues to live out a prosperous life, working long nights catching cuttlefish and spending mornings and evenings in his vineyard. He sometimes bathes his sons in the sea. He smiles with the same innocent kindness he had as a child and which his sons possess as well.
The book ends with the narrator returning to his initial question of whether he could "do it." The narrator reveals he wanted to keep the reader entertained while he drew a portrait of an ordinary fisherman who possesses the humble but uncommon quality of "goodness, just goodness."