At the age of 5, Marshman travelled with his parents and William Ward on an American ship called the Criterion to Bengal, arriving in Serampore on Sunday morning, 13 October 1799.

In April 1818, Marshman, together with his father Joshua, launched the first monthly magazine in Bengali, Digdarshan, which focused on educative information for the youth, and very shortly thereafter the weekly news magazine Samachar Darpan which was one of the two first Bengali newspapers (the other being Bengal Gazetti, published by Ganga Kishore Bhattacharya, in the first half of 1818).

The printing operations were so successful that they acquired their own substantial buildings by the river just north of the Mission Chapel.

In 1820, a steam engine was imported from Messrs. Thwaites and Rothwell, of Bolton, Lancashire, for the paper mill and was the first ever seen in India.

The Society was unwilling to take over the burden fully, but did offer to support a theological professor on the college staff.

He resigned his post as Official Bengali Translator to the Government and returned to England to Kensington Palace Gardens.

He was also long engaged on the writing of the history of India; his reading was very wide and he was a distinguished Oriental scholar.