He was appointed Surgeon, Royal Navy on 21 September 1805.
He served on HMS Swiftsure at the Battle of Trafalgar in October 1805 and on the Eurydice at Martinique in 1809, receiving medals for his service on both accounts
He was awarded the degree of M.D. on the 6th July 1814 by the Marischal College of Aberdeen. 
Peter Suther was employed as surgeon superintendent on the convict ship Mangles to Van Diemen's Land on 1 August 1835.
1841 - 1842
In the 1841 Census Peter Suther with his family, wife Sarah, daughter Mary Ann age 11, Sarah age 9, Henry age 5, Anna age 4 and Cuthbert age 2 were recorded at George Street, Woolwich Dockyard.
In 1841 Peter Suther surgeon of the William and Mary yacht, was appointed surgeon of the Woolwich dockyard
He was called on to testify at the inquest into the death of the chief engineer at the dockyard in September 1842 and gave assurances that cholera had not appeared at the dock yard despite rumours. 
1851 - 1856
Peter and Sarah Suther are recorded in the 1851 Census. Peter is 66 and Sarah 46. Their children give an insight into their different abodes. Mary was born c. 1829 at Halifax, Sarah Jane in 1831 at Bow, London; their son Cuthbert was born c. 1846 in Portsmouth and Anna was born in 1848 at Portsmouth. They also have two unmarried nieces residing with them Miriam Melville age 38 and Kate Allison age 23
Peter Suther was employed at the Chatham Dockyard in 1853 and was a member of the receiving party at the Dockyard when the Lords of Admiralty made an inspection in August 1853.
In July 1855 he was promoted to deputy inspector of hospitals and placed on the retired list.
In the 1861 Census the family resided at No. 4 Windsor Terrace Portsea with their unmarried daughters Sarah Jane and Anna and a male servant; Peter gives his occupation as Physician, and Deputy Inspector of hospitals RN, retired.
In 1864 almost sixty years after the Battle of Trafalgar, the United Service Magazine published a list of survivors of the famous battle. Peter Suther was accidentally omitted from the list but a later addition noted that he was the only officer of his rank alive in 1864 who had served on the memorable day when Nelson fell.
Peter Suther died on 21 March 1877 at Southsea, Portsea.
On 11 April 1877, The Will of Peter Suther M.D. and Inspector General of Hospitals and Fleets was proved at Winchester by Sarah Jane Suther of Southsea, spinster, his daughter. His effects were valued at under £600.