Along with Louise Glaum and Dorothy Dalton, she was one of the principal leading ladies at Inceville, one of the first motion picture studios to make feature films in Los Los Angeles Williams appeared in more than one hundred films between 1910 and 1918, including starring roles in The Italian and William South. Hart"s western, Hell"s Hinges, both of which are included in the National Film Registry. The following year, a half page article and photo of Williams was featured in the debut issue of Motion Picture Story magazine making her the first film actress to appear in a fan magazine.
The success of The Italian (1915), in which she played the wife of an immigrant, resulted in her being typecast in roles as Latin characters.
In 1917, the Los Angeles Times noted, "Heretofore she has been known almost exclusively as a portrayer of Latin parts, simply because she was such success in that sort of a role in The Italian, in which she played the leading part opposite George Beban."
In 1917, Williams and several other of the important actors and directors from Inceville left the studio to join the newly formed Paralta Company. The Los Angeles Times wrote, "Now that she is at the head of her own company and has the right to choose her own stories, she will have all the freedom in the world to show her versatility." Williams first film with Paralta, and also the last film in her acting career, was a story of the Klondike Gold Rush, Carmen of the Klondike.
During her years with the Triangle studios, Williams had become known for her many gowns, and the phrase "forty famous frocks" was coined to describe her wardrobe. When Williams left Triangle for Paralta, the Los Angeles Times asked whether the famous frocks would move with her.
lieutenant reported, "Clara is now in a quandary.
She wants to get some more frocks, but if she does it will spoil the phrase "forty famous frocks," and that would never do."
While working at the Ince studios, Williams met director Reginald Barker. He directed her in numerous films, including The Manitoba from Oregon (1915), The Criminal (1916), Three of Many (1917), Paws of the Bear (1917), The One Woman (1918), and Carmen of the Klondike (1918), which was her last screen appearance. In late February 1928, the Los Angeles Times reported that Williams had undergone a major surgery for an undisclosed condition at the California Lutheran Hospital.
Her funeral was held at the Little Church of the Flowers, and her remains were cremated at Forest Lawn Memorial Park in Glendale, California.