John Creswell was born in Cecil County, Maryland, on 18th November, 1828. After graduating from Dickinson College, Carlisle, he studied law and was admitted to the bar in Baltimore in 1850.

A strong opponent of slavery, Creswell was a member of the Whig Party before joining the Republican Party. Creswell was elected to the 38th Congress and took his seat on 9th March, 1863.

Creswell, like other Radical Republicans, objected to Johnson's attempts to veto the Civil Rights Bill and the Reconstruction Acts and voted for his impeachment in 1868.

In 1869 President Ulysses S. Grant appointed Creswell as his Postmaster General. After resigning in 1874 he served before the Alabama Claims Commission (1874-76) before resuming work as a lawyer. John Creswell died on 23rd December, 1891.