Le Vaillant began acting soon after the family returned to England although he struggled to find work and spent nine years unemployed. Le Vaillant spent three series in BBC One drama Casualty playing Dr. Julian Chapman before starring as the title character in the prime-time BBC series Dangerfield. He quit the show in 1997, having married former Casualty star Nicola Jeffries two years earlier. He also appeared in the short-lived sitcom Honey for Tea.
He left TV acting and spent much of his time in India, while also maintaining a base in Brixton. He returned to acting in 2009 to play Edward Heath in the TV drama Margaret.
