Born in 1957 in Essex, Alex Jennings trained as an actor at the Bristol Old Vic Theatre School. He began his theatre career in 1985 and played a variety of roles including The Scarlet Pimpernel as Maximillien Robespierre. He earned acclaim in his role as Glumov in Too Clever by Hal at the Old Vic in 1998, winning the Olivier Award for Best Comedy Performance. He was nominated in the same category the following year for The Liar as Dorante.
At the National Theatre, Jennings has starred in The Winter’s Tale, Albert Speer and Collaborators. He has also been an active member of the Royal Shakespeare Company in plays such as Peer Gynt, earning his an Olivier Award for Best Actor, A Midsummer Night's Dream and Measure for Measure.
In 2002, he won another Olivier for playing Professor Henry Higgins in My Fair Lady at the Theatre Royal Drury Lane. He also starred alongside Zoe Wanamaker in His Girl Friday. He also played the role of Willy Wonka in Charlie and the Chocolate Factory, directed by Sam Mendes.
Outside the theatre, Jennings has appeared in a variety of films including The Queen opposite Helen Mirren, as Alan Bennett in The Lady in the Van opposite Maggie Smith and as Horatio in Bridget Jones.