Teams John Mercer played for

MiscellaneousHarrow School (1851)
 Northampton (1852)
 Exeter College, Oxford (1854-1855)
 Northamptonshire (1854-1856)
 Oxford University (1855)
 Gentlemen of Northamptonshire (1865)
 North Northamptonshire (1865-1868)
 West Drayton (1869)
 Rockingham Park (1869)