When The Call of the Wild was published in 1903, it was a resounding critical and popular success. Reviewers applauded this exciting adventure tale and viewed it as a welcome alternative to the popular fiction of the day. J. Stewart Doubleday, reviewing the novel in The Reader, praised London's "suggestion of the eternal principles that underlie [life]," admitting that "it is cruel reading—often relentless reading...But we forgive the writer at last because his is true! He is not sentimental, tricky; he is at harmony with himself and nature."

The Atlantic Monthly found "something magnificent in the spectacle of [Buck's] gradual detachment from the tame, beaten-in virtues of uncounted forefathers...and his final triumph over the most dreaded powers of the wilderness." Overall, the reviewer praised it as "not a pretty story at all, but a very powerful one."

London's reputation also extended overseas, where he was considered one of America's foremost writers. Yet in America, despite the early attention the novel received, The Call of the Wild came to be seen as escapist fiction most suitable for children. London was barely mentioned in the literary histories published in the 1920s and after, and he was dismissed by the New Critics, the prominent literary scholars of the 1940s and 1950s.

London's fiction, especially The Call of the Wild, continued to be popular with the reading public. It wasn't until the 1960s that scholars reassessed their opinions regarding London's work. Since that time a flood of critical and biographical material on London has been published, elevating him, once again, as one of America's most important authors.

Critical commentary on The Call of the Wild focuses on autobiographical aspects of the story, the nature of the novel's allegory, and the question of whether it can be considered an example of literary naturalism. Joan Hedrick views the novel as London's attempt to deal with his past. "London had consciously closed the book on his working-class past. That self dwelt in a black and slippery pit to be recalled only in dreams. But in The Call of the Wild London was able, through his canine hero, to return to the scenes of his past, and, having got in touch with them, to imagine a different future."

Andrew Flink maintains that the novel is London's attempt, "either consciously or unconsciously," to deal with one specific part of his past, namely his stint in prison. He draws extensive parallels between London's experiences as a prisoner and Buck's life in the Klondike.

Most critics agree that the novel functions as an allegory, at least on one level. Abraham Rothberg expresses this view: "London was not only treating animals like human beings, but treating human beings like animals, recognizing no essential difference between man and animal. In The Call of the Wild he equated men with dogs and wolves, and equated the harshness of the trail with the harshness of society, implying that force, savagery and cunning were equally the ways to success in both areas."

According to Charles N. Watson, Jr., the novel is "about society as well as about the wilderness—or rather...it is about the conflict between the two." In other words, the novel is more than a simple allegory about society; it is a complex rendering of competing ideologies. Watson addresses the debate regarding the novel's naturalistic theme. To Watson, The Call of the Wild embodies both "Zolaesque naturalism...a reversion to savagery, a process of degeneration" and "romantic primitivism," by conveying "the forward movement of an initiation rite, through which Buck attains maturity and even apotheosis as a mythic hero." This dualism is perhaps the most discussed aspect of the novel.

While a few scholars, including Mary Kay Dodson, perceive the novel as a perfect embodiment of naturalism, others, such as Earl J. Wilcox, argue that the "naturalism that characterizes this novel is not consistently developed." Jonathan Auerbach sums up most opinions on the issue when he states, "There is a massive set of contradictions about Buck at the heart of the narrative, which moves in two seemingly opposite directions: toward nature, from culture (the standard naturalist plot of decivilization), and a more troubled but also more passionate movement toward self-transcendence, which cannot be fully contained by the conventional naturalistic model."

Watson argues that it is precisely these contradictions that have made this novel appealing to readers and critics. In the novel he perceives "a fruitful tension between the naturalistic impulse, with its emphasis on society and environment, and the romantic impulse, which emphasizes the power of the exceptional individual to act on his own. Such a tension...is one of the most fundamental themes of American fiction." As critics continue to explore the complexity of The Call of the Wild, it is becoming recognized as one of America's most enduring classics.