Ratray was born in New York City, the son of Ann Willis and Peter Ratray. He started acting at the age of nine years in the movie Where are the Children? (1986). He starred as a youth in various other programmes and movies until his acting pinnacle in 1990 as Buzz McCallister, the mean older brother of Macaulay Culkin's character Kevin in Home Alone
. This role was continued in 1992 in Home Alone 2: Lost in New York, where the McCallister family journeys from Miami back to New York City of the United States to find their troublesome youngest member.
Ratray landed minor roles in Dennis the Menace (as Mickey, the boyfriend of one of Dennis's babysitters) and an episode as Martin in The Enforcers (1996). A further film role was The Prince and Me as the computer-obsessed room-mate of "Eddy," the royal Prince of Denmark. He was a regular improv actor on MTV's Damage Control, notably as a director of an erotic film called 'Crazy Motor Hos', in which he was dressed as a naval captain. Ratray appeared in the September 29, 2006 episode of Law & Order, "Avatar", as the mentally ill murderer Richard Elam. He was a lisping doctor in the movie Slippery Slope (2006). He performed as Jimmy Link in Serial (2007).
In late 2007, a documentary film crew followed Ratray's attempts to win the heart of US Secretary of State Condoleezza Rice. He used 'love disks' -- love letters set to music and images -- to serenade her,  and traveled from New York, to Alabama, Denver, Palo Alto and Washington DC to court her. The resulting movie, Courting Condi, was due for international release in fall 2008.
Ratray is part of a band he formed himself called Little Bill and the Beckleys in which he performs as the band's lyricist, vocalist and electric guitarist. The band has performed live on a number of occasions in New York (where the group initially formed).
Ratray has appeared as a contestant on the game show Cash Cab, and subsequently lost.
Ratray made a minor character appearance in the 2009 film Surrogates.
In 2009, he was a guest star on the fifth season of Supernatural in the episode "The Real Ghost Busters".