Yusaku Kudo is a famous mystery novelist married to Yukiko Kudo. The two have one son, Shinichi Kudo.
He is known around the world as being the writer of a popular mystery novel series starring the Night Baron (called Knight Baron in Case Closed). Twenty years prior to the start of the series, he helped Inspector Megure solve difficult cases, much as his son does in the beginning of the series. However, Yusaku never sees himself as anything but a writer. Because of his fame, he and Yukiko move to Los Angeles one year before the story begins, leaving their then-fourteen-year-old son behind to complete his schooling. Before leaving, and when Shinichi was still a 10 year old kid, he and the previous KID, used to be rivals. It was hinted in episode 472-473 that he may know the original KID's secret identity. Oddly enough, he was the one who named the previous KID, reading 1412, as KID, making him technically a parent of KID, and Shinichi's brother, figuratively through episode 471-473.
The Kudo couple make their first appearance in episode 43. They are shown to have become worried because sense Shinichi turned into Conan, he has not called them (which is a few months). They ask Dr. Agasa about the problem. Agasa tells them about Shinichi's poisoning and his double life as Conan. In an attempt to convince Conan that he should join his parents in Los Angeles, Yusaku disguises himself the Night Baron and Yukiko disguises herself as Fanny Edogawa. With Dr. Agasa's help, they stage a mock kidnapping in an attempt to prove to Shinichi that he can't pull it off on his own, and to convince him to go live with them in America.
In episode 96, Yusaku appears once again, this time in an attempt to sharpen Conan's skills, although the fact that Yusaku is the mysterious man is not revealed until the end. It turns out that he had also come to win Yukiko's forgiveness for some offense and to take her back home with him.
He also helps to design a Sherlock Holmes virtual video game in the 6th movie, that Conan and his friends get trapped inside of.
As his son can be compared to Sherlock Holmes he would be compared to Sherlock's older brother Mycroft. As he is a better detective but chooses not to be one.