Major General Gwyn Jenkins from the Royal Marines is to be appointed the new Vice-Chief of the Defence Staff.
In the rank of general, he will succeed Admiral Sir Tim Fraser in September.
"I am delighted to congratulate Major General Gwyn Jenkins on his promotion to general and appointment as Vice-Chief of the Defence Staff," the Defence Secretary said.
"This courageous officer will bring a broad range of skills and extensive experience of the operational domain to his new role and I look forward to working closely with him," Ben Wallace added.
The Chief of the Defence Staff also congratulated Major General Jenkins and said he is "pleased" to welcome him to the role.
"An outstanding Royal Marine of his generation, he brings huge operational experience to the role at a pivotal time for global security," Admiral Sir Tony Radakin said.
"General Gwyn is also an innovator, with the instincts and ambition needed to help transform the Armed Forces to become even more lethal, capable and active in the world.
"I look forward to working with him to unlock the extraordinary potential that exists within Defence to contribute even more to our nation’s security and prosperity," he added.
Discussing his upcoming appointment, Maj Gen Jenkins said he is "very honoured" and looks forward to working "with our amazing military and civilian team in defence as we labour to protect the UK, its citizens and its interests".
Who is Major General Gwyn Jenkins?
The new Vice Chief of the Defence Staff's career in the Armed Forces began in 1990 when he was commissioned into the Royal Marines.
He spent time as a junior officer in the Commando Logistics Regiment and served on operations in Northern Ireland with 42 Commando Royal Marines.
Later, he joined the Special Forces and served as Troop and Squadron Commander with the Special Boat Service on operations around the world.
In 2004, he completed a Master's degree in Defence Studies at the Military College Shrivenham, after which he went on to serve as a lieutenant colonel before being appointed Commanding Officer Special Boat Service in 2009.
He was later promoted to colonel and deployed to Afghanistan for 12 months, for which he was awarded an OBE, returning to the UK in 2012 as the Military Assistant to the Prime Minster.
After two years at Number 10, he completed the Higher Command and Staff Course and was promoted to brigadier, taking up a civilian appointment in the Cabinet Office as Deputy National Security Advisor for Conflict, Stability and Defence.
In April 2017, he moved back to the military and took command of 3 Commando Brigade.
Two years later, in January 2019, he was promoted to major general and served in the Royal Navy as the Assistant Chief of Naval Staff and subsequently commanded a tri-service HQ.