Kevin, 68, was last seen in the Boxgrove area at around 10pm on Wednesday, December 14.
His car has since been located in Cocking Hill, Midhurst, where he often goes walking.
It is out-of-character for Kevin not to contact his family, and as such concern is growing for his welfare.
Kevin is American and described as slim, around 5’ 8” and with short grey hair.
Anyone who has seen him or has any information on his whereabouts is asked to call Sussex Police on 999, quoting serial 615 of 18/12.
