The Central Pacific Railroad hired its first dozen or so Chinese workers in 1864, and 50 more were taken on in 1865, in part to break a wage strike by Irish employees. Charles Crocker, the Central Pacific's contractor and one of the "Big Four" railroad barons (a group which included Collis Huntington), reportedly overcame opposition to hiring the Chinese by arguing that their ancestors were, after all, responsible for erecting the Great Wall.

Crocker's strategy of hiring the Chinese was successful on multiple levels. Fearing the loss of their jobs, Irish laborers quickly returned to work. Despite the common prejudice that Chinese laborers lacked sufficient stamina and intelligence, they proved reliable at track laying and other tasks. The Chinese later showed skill at more complicated endeavors, among them blasting away the granite cliffs of the Sierra Nevada range to make way for the tracks.

As the need for rail labor outstripped the supply of willing Americans and Europeans, recruiters began soliciting workers in China itself, mostly from Canton (now Guangzhou) Province. During the final push to complete the railroad, the Chinese constituted as many as 12,000 of the Central Pacific's 15,000 workers, and about 90 percent of those laying track. According to a book published in 1867, the Chinese laborers received $31 a month without board, while the Irish were paid $30 plus board.

While testifying before a congressional committee a few years after the railroad's completion, Crocker described his Chinese workforce as equals of their Irish counterparts on the job, and far superior off it. Because they were "all temperate," Crocker remarked, the Chinese were less prone to absenteeism, drunkenness and brawling than other workers. Historians have pointed out that other habits, including drinking tea which required boiled water, reduced the number of days missed for health-related reasons such as dysentery. Despite their healthier lifestyle, however, as many as 150 Chinese (some estimates are higher) died in blasting and other work-related incidents.

The goal of that congressional committee was to justify limiting Chinese immigration to the United States, but Crocker repeatedly praised the achievements of the Chinese and their work ethic. James Strobridge, Crocker's construction superintendent, also testified that he'd initially been "very much prejudiced" against using Chinese labor but that in fact the Central Pacific had virtually built its portion of the road by doing so.