Culme-Seymour was born in
Northchurch,
Berkhamsted 13 March 1836, the son of Sir John Hobart Culme-Seymour, 2nd Baronet (1800–1880) and his wife Elizabeth Culme, daughter of Reverend Thomas Culme. He entered the Navy in 1850, and in 1856 served as mate in , flagship of the East Indies squadron, which was involved in the
Second Opium War. In December 1870 he commanded in the
Channel Squadron. From 29 July 1879 to 9 May 1882 he was captain of , 1885 saw him as second in command of the Baltic squadron under Phipps Hornby during the
Panjdeh Incident. From 3 May 1893 to 10 November 1896 he was
Commander in Chief, Mediterranean Fleet, In 1899 he was appointed
First and Principal Naval Aide-de-Camp to
Queen Victoria. He was re-appointed after the succession of the new King
Edward VII, in February 1901, but resigned from the position in April the same year. On the death of Queen Victoria, Culme-Seymour took part in the procession from Osborne House to Trinity Pier on 1 February 1901, taking up position immediately behind the gun carriage carrying the coffin. He then accompanied the coffin on board
HM Yacht Alberta. In early 1901 Sir Michael was asked by
King Edward to take part in a special diplomatic mission to announce the King's accession to the governments of
Belgium,
Bavaria,
Italy,
Württemberg, and
The Netherlands. He was granted the honorary offices of
Vice-Admiral of the United Kingdom and
Lieutenant of the Admiralty in July 1901, and kept these until his death. He died at
Oundle in
Northamptonshire in 1920. ==Honours==