He took part in the campaigns in the Netherlands and Egypt under Sir Ralph Abercromby, he was promoted to the rank of major in 1803 and a lieutenant colonel in 1804. From 1806 to 1811 he was stationed on Sicily. Between 1812 and 1813 he was in Spain fighting in the Peninsular War, where he was severely wounded at Alicante. On 12 April 1813, while commanding the Light Brigade in John Murray's expeditionary force, Adam led a brilliant rearguard action against the corps of Marshal Louis-Gabriel Suchet at Biar. The following day, his 2/27th Foot battalion inflicted 350 casualties on Suchet's 121st Line Regiment during the Battle of Castalla. He was wounded again in an action at Ordal on 13 September 1813.