Bryan was an Old-Earth creationist, not quite like your Ken Ham types nowadays. He was not a fundamentalist by the standards of his day, unless you want to consider basically everyone of his day a fundamentalist.
Bryan was considered a fundamentalist in the 1920's, was widely referred to as such, and addressed self-described fundamentalist organizations:
"In order to organize for combat and initiate strategies for defeating evolution, fundamentalists formed the World’s Christian Fundamentals Association (WCFA) in 1919. Its agenda included a definite plan to purge schools, seminaries, and pulpits of liberals and heretics. The “heresy” of evolution was at the top of the list. In 1924, William Jennings Bryan made an appearance at the WCFA convention in Minneapolis. Gasper states that “this event raised the enthusiasm of the Fundamentalists to a new high. They now had a nationally known and popular figure to lead them in their crusade.”22 It was this Christian statesman who, two years before the meeting, brought fundamentalism to national attention through his relentless attacks on evolution.2"
http://www.dbts.edu/journals/1999/priest.pdf
To say that "basically everyone of his day" was a fundamentalist in Bryan's sense is absurd (even if you limit "everyone" to Protestants). How could there have been a Modernist-Fundamentalist split that affected so many Protestant denominations if everyone was a Fundamentalist and there were no Modernists?! It is true of course that neither the Modernist nor the Fundamentalist camp was monolithic. Bryan for example did not believe that the "days" referred to in Genesis were necessarily 24-hour days:
Q--Would you say that the earth was only 4,000 years old?
A--Oh, no; I think it is much older than that.
Q--How much?
A--I couldn't say.
Q--Do you say whether the Bible itself says it is older than that?
A--I don't think it is older or not.
Q--Do you think the earth was made in six days?
A--Not six days of twenty-four hours.
Q--Doesn't it say so?
A--No, sir....
Q--Then, when the Bible said, for instance, "and God called the firmament heaven. And the evening and the morning were the second day," that does not necessarily mean twenty-four hours?
A--I do not think it necessarily does.
Q--Do you think it does or does not?
A--I know a great many think so.
Q--What do you think?
A--I do not think it does.
Q--You think those were not literal days?
A--I do not think they were twenty-four-hour days.
Q--What do you think about it?
A--That is my opinion--I do not know that my opinion is better on that subject than those who think it does.
Q--You do not think that ?
A--No. But I think it would be just as easy for the kind of God we believe in to make the earth in six days as in six years or in 6,000,000 years or in 600,000,000 years. I do not think it important whether we believe one or the other.
Q--Do you think those were literal days?
A--My impression is they were periods, but I would not attempt to argue as against anybody who wanted to believe in literal days.
http://law2.umkc.edu/faculty/projects/ftrials/scopes/day7.htm
But Bryan's differences with what are now called "young earth creationists" were generally regarded as differences *within* the fundamentalist camp. On the Fundamentalism vs. Modernism controversy which raged in the 1920's, there was no question where Bryan stood.