After a positive start to life at The Hawthorns, his form declined up until the run-in in which he scored an audacious lob from 35 yards in the thrilling 3–3 draw against fellow relegations rivals Cardiff City on 29 March 2014. He followed that strike up the following week with the solitary goal in West Brom's away win over Norwich City. Upon finishing his loan at West Brom, he returned to Marseille in July 2014.
On 1 September 2014, Amalfitano signed for West Ham United on a one-year deal for an undisclosed fee. He made his West Ham debut two weeks later against Hull City on 15 September, replacing Diafra Sakho in the second half of the 2–2 draw.
On 20 September 2014, Amalfitano made his home debut for the Hammers, coming on in the second half and scoring his first goal for West Ham, against Liverpool, to complete a 3–1 victory and secure the club's first home win of the season. Amalfitano's second goal for the club came on 25 October at home to Manchester City when he netted the opener in a 2–1 victory over the reigning champions.