Why was actress Cristin Milioti cast as the "Mother" in How I Met Your Mother? The titular character's identity was kept a mystery for most of the series, until she made her first official appearance in the season 8 finale.
The story about how Ted Mosby (Josh Radnor) met the Mother was the central focus of the series. As Ted was sharing his memories with his children, he revealed key details surrounding the woman. Before ever seeing the Mother, the audience knew that she played guitar, went to the same St. Patrick's Day party which featured the "Bump Girl," and was the roommate of one of Ted's past girlfriends. The Mother was shown a few times indirectly, most notably in a scene holding a yellow umbrella.
The identity of the Mother wasn't the only major revelation surrounding the character; the casting decision was also a big deal. The Mother, who was actually named Tracy McConnell, was portrayed by Cristin Milioti. After her debut in the season 8 finale, she was promoted to a main character for the ninth and final season. Through Tracy's point of view, many gaps left in Ted's story were finally filled. Tracy sadly met a tragic end, as it was revealed that she passed away prior to Ted's storytelling. But before that, the Mother role was one of the most sought after parts in TV at the time. So why did the role go to Milioti?
When the Mother was being cast in the sitcom, the crew behind the show didn't want a big name that the audience would already be familiar with. Being well-known as an actor often comes with preconceived notions, something they wanted to avoid. The casting director Marisa Ross had seen Milioti in her past roles on The Good Wife, Nurse Jackie, and 30 Rock. The more they saw of her, the more they wanted her for the role.
Series co-creators Carter Bays and Craig Thomas have stated that Milioti was also appealing due to her musical ability. The character of Tracy has long been described as a band member, and it helped that the actress picked had knowledge of music. Milioti was a Broadway star prior to her casting on the series. She performed in the musical adaption of Once, which garnered her a Tony Award nomination.
Milioti didn't even watch How I Met Your Mother before her debut scene in season 8. She eventually binged the entire series to get a better understanding of the character. The actress had no trouble clicking with the cast as they felt like they already knew her. Even though her time on the series was brief, Milioti's portrayal as the Mother made a long-lasting impact.