Alan Rickman obituary: He loved the baddies he played

Alan Rickman, who has died of pancreatic cancer aged 69, was a great actor of self-invention. Born and raised on a council estate in Acton, west London, he trained first as a graphic designer before going to RADA aged 26. From humble beginnings he became a stylish, sonorously spoken star of the RSC and, in his last film (which he also directed), A Little Chaos, Louis XIV in all his pompous glory at Versailles.

He was a back-foot actor who surprised everyone with the comic flair and attack of his Elyot Chase in Noel Coward's Private Lives, playing opposite his great friend and colleague Lindsay Duncan in a Howard Davies production that triumphed in the West End and on Broadway.

To the general public he was best known as the dastardly Sheriff of Nottingham with Kevin Costner in Robin Hood, Prince of Thieves; or as the German terrorist Hans Gruber opposite Bruce Willis in Die Hard; or again, and especially, as the slithery Severus Snape in the Harry Potter movies, a wonderful creation that developed intriguingly through all eight films; his brand of malevolence was always tinged around the edges with a languid self-mockery.

He was a marvellous, if slightly over-age, Hamlet in the early 1990s, but his stage golden age was in the mid-1980s at the RSC when he created the role of the Valcomte de Valmont (currently played by Dominic West at the Donmar Warehouse) in a dream production (again, by Howard Davies) of Christopher Hampton's Les Liaisons Dangereuses. He gleamed and nibbled like a poisonous snake in a cast that included Juliet Stevenson, Fiona Shaw and Lesley Manville. In the same Stratford season, which transferred to the Aldwych in the pre-Barbican days, he was the definitive sulky Achilles in Troilus and Cressida and the equally definitive nonchalant misfit Jaques in As You Like It.

With Stevenson he appeared memorably in Anthony Minghella's Truly, Madly, Deeply, a beautiful low-budget 1991 film of loss, grieving and indelible love. Rickman was himself a great supporter of low budget movies, just as he was a crucial player in the Bush and Royal Court of the 1980s, when he graced – and he really did "grace" with his acting – the plays of Dusty Hughes, Snoo Wilson, Aphra Behn (the first female British playwright) and Stephen Poliakoff. He was primus inter pares in his generation, always the star of the ensemble, the truly "great" actor in a generation that was cast into shadow, in a way, by the likes of Ian McKellen, Alan Howard and Ian Richardson.

Personally, I loved everything he did, even when he infuriatingly swallowed his own words in his own vocal music. I even loved his critically reviled Antony at the National opposite Helen Mirren's voluptuous Cleopatra; the two of them were, obviously, very sexy, and he played the old warrior as a washed-up has-been with a poet's soul.

This was the thing. He let you see right through him, and the apparatus of his effortless technique, by dint of more than a hint of self-mockery and a lot of self-knowledge. He loved the baddies he played as much as the (very) occasional good guy. And so did we. It's a terrible loss, and members of his profession across the world are devastated.