Kurt Cochran, in his 50s and from Utah, is believed to have been killed while walking on Westminster Bridge when a car mowed down pedestrians, the Telegraph reports.
Cochran’s wife, Melissa, was reportedly also injured in the attack and is in hospital with a broken leg, rib and a cut on her head.
Shantell Payne wrote on Facebook: "With a heavy heart I must pass the sad news of our beautiful brother, father, husband, son and friend Kurt Cochran.
"He could not overcome the injuries he received in the London terror attacks.
"This pain is so heart wrenching and raw it has rocked our family and all that knew him to its core."