Pte Alex Stringer, 23, of Canvey Island, Essex, lost both legs and an arm in Afghanistan in 2011.
Basildon Crown Court heard how his friend Conor Aldous, 22, acted as Pte Stringer's carer.
During that time, in 2012, Aldous stole Â£2,500 from him. He was jailed for 10 months after admitting theft.
The court heard how Aldous, shortly after he stole the money from Pte Stringer, helped him walk down the aisle on artificial legs.
Judge David Owen-Jones, sentencing, said: "It was a mean offence.
"He was extremely vulnerable and you abused that trust.
"It is a very serious offence and only an immediate custodial sentence can be justified."
Aldous, of Grays and who was accompanied to court by his pregnant girlfriend, showed no reaction as sentence was passed.
His partner broke down in tears as Aldous was led to the cells.
The best man of a soldier wounded in Afghanistan has been jailed for stealing thousands of pounds from his friend weeks before his wedding.