Born Ubbe Eert Iwwerks, he was the animator of the first Mickey Mouse cartoon.
Ub was my maternal grandfather's cousin.
Less than a year after meeting, Iwerks and Disney joined together and formed a company, in 1920, called Iwerks-Disney Commercial Artists. The venture was short lived, however, as Walt went to work for the Kansas City Film Ad Company for more money. It wasn't long before Disney had convinced Kansas City Film Ad Company that it also needed the talents of Ub Iwerks. Iwerks was hired.
<snip>
While Disney went off on new adventures, Iwerks remained in Kansas City faithfully working for the Kansas City Film Ad Company. But it wasn't long before Iwerks received word from Disney that his services were needed in California.
In 1924, Iwerks moved to California to join forces again with Disney who had formed Disney Brothers Productions (later changed to Walt Disney Studios). Iwerks was paid less money, but received 20% ownership in Disney Brothers Productions as additional compensation.
Iwerks was put in charge of a cartoon that quickly became very popular for its time — "Oswald the Lucky Rabbit." The popularity of the Oswald series and greed of the distributor, Charlie Mintz, led to a dispute over ownership rights. Charlie Mintz won. In addition, nearly all of Disney's animators deserted him for Mintz. One of the few to remain was the faithful Ub Iwerks. Iwerks loyalty created a bond of trust that very few people ever held with Disney.
Soured by the Oswald rabbit events, Disney came up with a new character idea — Mickey Mouse. Together, Disney and Iwerks developed the idea and personality for Mickey Mouse. Iwerks was then given the task of bringing Mickey Mouse to life. Suddenly a new Hollywood star was born.
Iwerks was Disney's right hand man in the creation of the early Mickey Mouse cartoons. Disney would come up with the ideas, stories, and motivations, then Iwerks would bring it to life. Bringing Mickey Mouse to life, however, was no easy task and it required Iwerks to spit out 600 drawings every single day. Iwerks dedication, however, would soon payoff for him and Disney. The third Mickey Mouse cartoon that Disney directed and Iwerks animated, "Steamboat Willie," would be the one that would catapult Mickey and Disney into stardom and household names.
more at link...
http://www.digitalmediafx.com/Features/ubiwerks.html