John Strong, Jr. (April 7, 1830 – April 2, 1913) was a politician from the U.S. state of Michigan.
Strong, the son of John Strong Sr. (1798–1881), from Wroxton, Oxfordshire, England, was a first generation American born in a log cabin in Greenfield Township, Michigan, which is now part of Detroit. He received a common school education and engaged in farming. In 1863, he moved to Monroe County where he founded South Rockwood and engaged in milling, manufacturing barrel staves, heading, lumber, merchandising, farming and raising cattle. During a sawmill accident, he lost two fingers on his right hand. He married Emily Buhl, the sister of two Detroit mayors, Frederick and Christian H. Buhl. His nephew John Strong Haggerty (1866–1950) served as Michigan Secretary of State from 1927 to 1931.
In 1860, Strong was elected as a Democrat to the Michigan House of Representatives from Wayne County (2nd district), just as his father had been from 1835 to 1836, and served from 1861 to 1862. In 1878, he was again elected to the state house, yet instead from Monroe County (2nd district) and served from 1879 to 1880. In 1880, he was elected to the Michigan Senate from the 5th district and served from 1881 to 1884.