In 1963, when the first press reports on the show appeared, it was mentioned in some of them that Michael Redgrave was being sought to play the leading role. At this time, the lyricists for the show were to be W. H. Auden and Chester Kallman. In 1964, it was reported that Rex Harrison was trying to put together a season of three “small” musicals to play in repertory in London. The reports said that one of them was to be an adaptation of Don Quixote with lyrics by Auden. Earlier press reports suggest that it was Harrison who sought out the show's creators rather than vice versa.
A number of sites report that Harrison was offered the role, but withdraw from the production when he realized that the singing demands were too great for him to handle, but we have found no trustworthy source that confirms Harrison's possible involvement went that far. That doesn't mean the story isn't true, but we have found no reliable source for the story. Two biographies of Harrison — Roy Moseley's Rex Harrison: A Biography, and Alexander Walker's Fatal Charm: The Life of Rex Harrison — offer a different story. Both state that Harrison lost interest when Auden was no longer involved.
In 1972, Harrison starred in The Adventures of Don Quixote, a BBC Play of the Month production that was also shown on American television.
When the production opened, there was no song list in the playbill, but one was eventually added.
Man of La Mancha won the New York Drama Critics Circle award for best musical of the 1965-1966 on the first ballot with eight votes from the fourteen voting members that year. Mame received three votes, and It's a Bird...It's a Plane...It's Superman! and The Mad Show each received one vote. There were two abstentions.
The production received five Tony awards. The show won Best Musical; Richard Kiley won for Actor (Musical); Mitch Leigh and Joe Darion received the award for Composer and Lyricist; Albert Marre received the award for Director (Musical); and Howard Bay was voted the outstanding Scenic Designer. No award was given book of a musical, but Dale Wasserman, author of the show's book, received the Best Musical award, along with the producers.
The production was cited by the Variety Poll of Drama Critics in three categories: Richard Kiley won for Actor in a Musical; Mitch Leigh won for Score; and Howard Bay won for Scene Designer.
Some online sources list the number of previews as having been 21, but the correct number would seem to be 27, based on the dates that previews started and ended and the performance schedule during that time. We have found no evidence of any previews having been canceled.
It is sometimes incorrectly stated that the production opened Off-Broadway. The ANTA Washington Square, although outside what is generally considered the Broadway theatre district, was considered a Broadway house during the several years of its existence. During the run of Man of La Mancha, the seating capacity was 1,136, well above the upper limits for Off-Broadway. The production operated under Broadway contracts. The Tony Awards deemed it to be a Broadway production, as did Best Plays and Variety.
The production was capitalized at $200,000, which was low for the time period.
