During 1986-1988, he commanded 3rd Battalion, 8th Marines, 2nd Marine Division.
In 2009, Genn embedded himself with the 3rd Battalion 8th Marines at Forward Operating Base Gulistan in Farah Province, central Afghanistan, where he drew sketches of that unit's actions in the Global War on Terror.
8th United States Congress | Royal Marines | Battalion | 3rd Rock from the Sun | Marines | 8th | South Carolina's 3rd congressional district | battalion | Robert Gascoyne-Cecil, 3rd Marquess of Salisbury | Michigan's 3rd congressional district | Captain (British Army and Royal Marines) | Thomas Fairfax, 3rd Lord Fairfax of Cameron | 3rd United States Congress | Fernando Álvarez de Toledo, 3rd Duke of Alba | 3rd arrondissement of Marseille | 1st Battalion 8th Marines | Henry John Temple, 3rd Viscount Palmerston | 1st Battalion 9th Marines | Thomas Radclyffe, 3rd Earl of Sussex | Richard of York, 3rd Duke of York | John Stuart, 3rd Earl of Bute | Frederick Hervey, 8th Marquess of Bristol | Alabama's 3rd congressional district | 8th arrondissement of Paris | 3rd Battalion | William Cavendish-Bentinck, 3rd Duke of Portland | Sir Frederick Pollock, 3rd Baronet | Revolutionary Movement 8th October | Mormon Battalion | Lionel Tollemache, 8th Earl of Dysart |