Josh Radnor played the role of Ted Mosby for the duration of How I Met Your Mother, but Bob Saget was the actor to voice the older version of the character. Saget served as the narrator for nearly every episode of the CBS sitcom from Carter Bays and Craig Thomas. Though the actor never directly appeared in the series, his involvement was integral as it became the plot's driving force. However, some viewers always wondered why Radnor wasn't picked to narrate the sitcom since he was the face of the role.
For nine seasons, Ted documented the journey that led up to the eventual meeting of the mother of his two children, Penny and Luke. As the events played out in How I Met Your Mother, a version of Ted from 2030 was telling the grand story to his teenage kids, which subsequently served as the narration. While the lives of Marshall Eriksen, Lily Aldrin, Robin Scherbatsky, and Barney Stinson also came into focus, the plot always circled back to Ted and the first encounter with his future wife, Tracy McConnell.
When How I Met Your Mother was still in the development stages, Saget was contacted to act as the narrator since the series wanted to emulate a feel made popular by The Wonder Years. The coming-of-age series premiered in the late '80s, but it followed characters twenty years prior. While a young Fred Savage starred as the lead character, Kevin Arnold, actor Daniel Stern voice the older version of the figure to serve as a narrator. Some viewers of How I Met Your Mother assumed Saget was hired since he was linked to one of the most well-known fathers in sitcom TV history, playing Danny Tanner on Full House from 1987 to 1995. While his voice provided a sense of familiarity, that wasn't the distinct reason Saget was hired.
HIMYM Needed To Differentiate Between Ted & Future Ted
More than anything, How I Met Your Mother needed a narrator to act as a storytelling device. Future Ted's tale steered the events of the series while also providing more insight into memorable moments. By not using Radnor's voice for the narration, viewers could differentiate when Future Ted was doing the voice-over. Granted, the narration usually occurred at the beginning and ends of episodes, but that wasn't always the case. When Saget's voice jumped into a scene, it was established that the voice was coming from Future Ted. This method lessened confusion when it came to the presence of the same character from different timelines.
Oddly enough, Saget was never credited for his work on How I Met Your Mother, even though his narrating remained a key aspect of the show's entire run. When Future Ted was finally shown in the series finale, Radnor took over with an aged appearance. Viewers quickly pointed out the inconsistency with Radnor's voice not sounding anything like Future Ted's narration. There was, however, a belief that Saget's version was more like the voice of Ted's subconscious. In reality, the series most likely wanted the Radnor to finish Ted's journey in the future timeline.