Laishun then traveled to China, and following several years of working as a missionary assistant in Guangzhou he left with his family to pursue a trading career in Shanghai.

Zeng settled with his family in Springfield, Massachusetts, and began giving public lectures on Chinese society alongside his participation in local civic life.

He was briefly dispatched to Cuba around the end of 1873 to investigate the poor working conditions of Chinese indentured servants brought to the island as part of the coolie trade.

He was abruptly recalled to China in late 1874, likely for diplomatic purposes; during his return, he traveled through Europe to assess universities for future educational missions.

He became the Chief Private English Secretary of the statesman Li Hongzhang and served as an interpreter in various diplomatic negotiations with the western powers over the following two decades.

There, in 1836, he was noticed by American Board of Commissioners for Foreign Missions missionary Joseph Travelli, who had him enrolled in a Chinese day school established by his colleague Ira Tracy the previous year.

[3] Around April 1843, Zeng was sent to the United States with the Presbyterian missionary John Hunter Morrison, who was returning to America after work in northern India.

Morrison returned to India in 1846, and Zeng was put into the care of an American Board missionary previously stationed in Guangzhou, Samuel Wells Williams.

Williams arranged for the First Presbyterian Church in Utica, New York, to support Zeng's study for two years, with the "faculty offering to teach him gratuitously, and the ladies in Brooklyn to clothe him.

[7][b] At Hamilton, Zeng studied the New Testament in Koine Greek (likely under Edward North) and taught Sunday school at a local church.

[9] Zeng arrived in the British colony of Hong Kong, and attempted to secure a position teaching at the Morrison Educational Society.

[13][14][15] Zeng fared well in business, with an American Episcopal missionary who visited him in 1856 writing that "some profitable employment in the foreign community, and every token of prosperity surrounds him".

They met with one of the rebellion's chief political leaders, Shield King Hong Rengan, to attempt to ascertain the beliefs of the Taiping rebels and their likelihood of success.

[17] Following the end of the Taiping Rebellion and China's defeat in the Second Opium War, the Qing government began the Self-Strengthening Movement, seeking to modernize and gain equal footing with the western powers.

Zeng was hired by the imperial general Zuo Zongtang in 1866 as an English teacher at the newly-established Fuzhou Navy Yard School.

[18] In August 1871, political and military leaders Zeng Guofan and Li Hongzhang submitted a memorial to the Qing court calling for a group of 120 Chinese boys to be sent to study in the United States for a period of fifteen years, in order for them to become familiarized with western practices and institutions.

The memorial was soon approved by Prince Gong, the head of the Zongli Yamen (the chief foreign policy office), and then the imperial court itself the following month.

[21] A preparatory school for the mission's students was established in Shanghai, with Zeng appointed as the English teacher and his teenage sons Elijah and Spencer as assistants.

[22] In August 1872, Zeng departed from Shanghai aboard the Pacific Mail steamer Costa Rica along with his family, Chen, and the first party of 30 students – which included his son Spencer.

"[28] Zeng also gave sermons to church audiences and Sunday schools, predicting that Christianity would be increasingly persecuted in China before eventually rising to power.

[30] He was introduced to Grant at a White House reception, where Zeng gave him well-wishes on behalf of the Chinese government and hoped for future Sino–American relations to be "as pacific as the ocean which rolls between them.

Prince Gong, concerned by reports from missionary Samuel Wells Williams, petitioned the Tongzhi Emperor to send a commission to Cuba to investigate.

He traveled to Havana in late 1873 or early 1874 to discuss the laborers' working conditions with American and British diplomats, staying around ten days before returning to the United States.

The mission's reports led to increased international pressure against Spain, leading to an 1877 Sino-Spanish treaty ending the practice and returning workers to China.

[36][37] In December 1874, shortly after welcoming the third detachment of students for the mission, Zeng was abruptly recalled to China on official business, most likely relating to negotiations on ending the coolie trade with Spain and Peru.

[38] The Springfield Daily Republican reported that Zeng had been dismissed from the mission due to court intrigue, but had managed to regain political standing after meeting with Li Hongzhang.

His wife and children sold their house in Springfield and set off back to China in September 1873; his eldest sons Spencer and Elijah stayed behind to continue their studies at Yale University.

Spencer became a journalist and official; he wrote for the North China Daily News until 1906, before moving to Nanjing to serve as an intendant and foreign affairs deputy on the staff of Governor-General Duanfang.