What is the origin of the phrase "Kangaroo court"?

Chambers Dictionary defines: A court operated by a mob, by prisoners in jail, or by any improperly constituted body; a tribunal before which fair trial is {impossible;} a comic burlesque court. It would seem that the saying must be Australian in origin, but I don't know how or when.

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Kangaroo Court
Term descriptive of a sham legal procceding in which a person's rights are totally disregarded and in which the result is a forgone conclusion because of the bias of the court or other tribunal

Source: Black's Law Dictionary, Sixth Edition
http://ejguisteonlawandjustice.blogspot.com.au/2016/04/kangaroo-court-origins-of-term-and.html

Further to the answers already given, little is known about the etymology. What is known is that the first kangaroo courts originated in the United States at approximately the time of the 1849 California Gold Rush, and the word saw its earliest use in the southwestern U.S.%97it first turned up in print in 1853 in a book about Texas. It has been suggested that kangaroo courts got their name because they were initially marked by rapid and unpredictable movement from one place to another, or that they were in some way associated with Australian miners or with 'jumping' (i.e., illegally occupying) mining claims. These hypotheses are all unsubstantiated, however.

https://www.phrases.org.uk/meanings/kangaroo-court.html

The concept of kangaroo court dates to the early nineteenth century. Scholars trace its origin to the historical practice of itinerant judges on the U.S. frontier. These roving judges were paid on the basis of how many trials they conducted, and in some instances their salary depended on the fines from the defendants they convicted. The term kangaroo court comes from the image of these judges hopping from place to place, guided less by concern for justice than by the desire to wrap up as many trials as the day allowed.

answers.com/Kangaroo%20court no longer exists

The term seems not to originate from Australia, the homeland of kangaroos as the oldest available evidence stems from the California Gold Rush, with the first written reference in 1853 in a Texas context (also mustang court), from the notion of proceeding "by leaps" like the agile marsupial. It is possible that the phrase arose out of a combination of informal courts convened to deal with "claim jumpers," the many Australian participants in the Gold Rush and a bit of word play. Examples of alleged kangaroo courts amount to "judicial lynchings..."

Kangaroo courts are judicial proceedings that deny due process in the name of expediency. The outcome of such a trial is essentially made in advance, usually for the purpose of providing a conviction, either by going through the motions of manipulated procedure or by allowing no defense at all. The term seems not to originate from Australia, the native continent of kangaroos, as the oldest available evidence stems from the California Gold Rush, with the first written reference (1853) in a Texas context (also mustang court), from the notion of proceeding "by leaps" like the eponymous marsupial. It is possible that the phrase arose out of a combination of informal courts convened to deal with "claim jumpers", such courts being named "kangaroo courts" by some of the many Australian participants in the Gold Rush together with a bit of local word play.

https://en.wikipedia.org/wiki/Kangaroo_court

One of the strangest aspects of "kangaroo court" is that the phrase is not originally from Australia, which is the only place you'll find actual kangaroos. The first "kangaroo courts" were informal tribunals set up to dispense instant justice in the American West in the 1850's, before conventional court systems existed on the frontier. Later on, "kangaroo court" was used to describe mock courts set up by penitentiary prisoners to intimidate and extort money from new inmates. Today we usually use the term to mean any court whose verdict is arranged in advance or otherwise clearly unfair.
So the question is why "kangaroo" was used to describe such mockeries of justice, and there are two basic possibilities. First, and most likely, is the theory you mention: that "kangaroo" is a sardonic analogy between the hopping gait of a kangaroo and the irrational and unpredictable conduct of the original frontier tribunals. Considering the leaps of logic and complete disregard for legal procedure likely to be found in such a proceeding, the comparison certainly seems apt.

http://www.word-detective.com/030299.html