Born in Leominster, Massachusetts, Crocker attended the public schools and Groton Academy. He was first employed in a paper mill at Franklin, New Hampshire in 1820. In 1823, he borrowed the money necessary to establish a paper mill at Fitchburg and served as proprietor of paper manufactories there. His paper mills became the largest in the United States and he built extensive machine shops and foundries in the neighborhood of his mills. In manufacturing white paper he was the first to use cotton waste and also the first to use palm leaf fibre in wall papers.
He served as president of the Fitchburg Railroad.
Crocker was elected as a Republican to the Forty-second Congress to fill the vacancy caused by the resignation of William B. Washburn (who was elected Governor). He was reelected to the Forty-third Congress and served from January 2, 1872, until his death in Fitchburg, Massachusetts, December 26, 1874. He was interred in Laurel Hill Cemetery.
The Science Channel documentary Driven to Invent: Killer Tunnel called Crocker "The Father of Modern Tunneling" for his influence in advancing the use of geologists, explosives, pneumatic tools, boring technology, and said, "He laid down the rules for tunnel construction even to the present day."