This was producer Jay Ward's first animated series and the first made-for-television cartoon series, but since it was sold city by city and not directly to a network, it isn't always recognized as the first animated TV-series (despite being broadcast in 1949, earlier than any other animated TV-series).
The original animation was done in black and white by Alex Anderson in his garage studio at 2727 Stuart St. in Berkeley, California.
The concept of the Crusader Rabbit was that of a crusading Don Quixote. The Crusader Rabbit pilot was about Crusader and Rags (Ragland T. Tiger) journeying to Texas where hunters were making life miserable for the Texas jack rabbits.
Although it was very popular in the markets where it played, production on the original series ended in 1951 due to lawsuits over ownership of the series.