[1] He was educated at Terrington Hall and Sedbergh School, studied for a degree in Mathematics at Grey College, Durham, and then at the Royal Academy of Dramatic Art.
[citation needed] Wilby's first appearance on screen was in the Oxford Film Company production Privileged (1982) alongside Hugh Grant.
His further roles included A Tale of Two Cities (1989) for Granada Television, Howards End (1992), Regeneration (1997), Ismail Merchant's Cotton Mary (1999), Gosford Park (2001), and Alain Robbe-Grillet's C'est Gradiva qui vous appelle (2006), co-starring Arielle Dombasle, which premiered at the Venice Film Festival.
On stage, Wilby starred in the 1995 revival of John Osborne's A Patriot for Me by the Royal Shakespeare Company at the Barbican Theatre.
[4][5] From 1994 to 2015, Wilby owned The Laines, an 18th-century country house in Plumpton, East Sussex, near Lewes.