1911 is about as far back as I can go and still single out individual acting performances for praise. Before this, film technique and storytelling didn't allow for much of a connection between the actors and the audience (they didn't even receive screen credits), and except for Asta Nielsen in Afgrunden (1910) and Max Linder's early comedies, actors were not much more than props holding up the scenery.
Speaking of Max Linder, I think his early work (pre-World War I) puts him on the Mount Rushmore of silent comedy with Charlie Chaplin, Buster Keaton and Harold Lloyd. By my count, I've seen 44 of his films and I can say with absolute metaphysical certitude that Max Takes Tonics is the best of them.
See it here and read a bit more about the triumphs and ultimate tragedy of Max Linder while you're at it.
I also wrote about the groundbreaking feature film L'inferno here, and the cartoonist turned animator Winsor McCay here.
winner: Winsor McCay, the Famous Cartoonist of the N.Y. Herald and His Moving Comics, a.k.a. Little Nemo (prod. Winsor McCay)
nominees: L'inferno (prod. Milano Film); The Lonedale Operator (prod. D.W. Griffith); Manhattan Trade School For Girls (prod. unknown); Max Victime du Quinquina a.k.a. Max Takes Tonics (prod. Pathé Frères)
winner: Max Linder (Max victime du quinquina a.k.a. Max Takes Tonics)
winner: Dorothy West (Swords And Hearts)
nominees: Linda Arvidson (Enoch Arden Parts 1 & 2)
winner: Francesco Bertolini, Adolfo Padovan and Giuseppe de Liguoro (L'inferno)
nominees: D.W. Griffith (The Biograph Shorts); Max Linder (Max victime du quinquina a.k.a. Max Takes Tonics); Winsor McCay (Winsor McCay, the Famous Cartoonist of the N.Y. Herald and His Moving Comics, a.k.a. Little Nemo)
Francesco Bertolini and Sandro Properzi (L'inferno) (Art Direction-Set Decoration); Emilio Roncarolo (L'inferno) (Cinematography)