Many articles will list the author's academic affiliation at the time of publication:
Byline of Jack R. Censer from Journal of Social History
The affiliation may be at the end of an article:
Affiliation of Martyn P. Thompson from Journal of the History of Ideas
Some articles will include a complete author biography:
Biography of Venus Bivar from Agricultural History
If an affiliation is not listed in that article's journal, search for other articles by the author that may list the affiliation.
For example, the article Art as National Propaganda in the French Revolution by David L. Dowd leads to the article Jacques-Louis David, Artist Member of the Committee of General Security in The American Historical Review, which shows that Dowd was at the University of Florida.
Once you have the author's name and affiliation, you can use Google to search for additional information.
This may find an author's biography on their university website.
For example, Tulane University includes a biography of Martyn P. Thompson
Or an author's personal website, like this one for Burton W. Peretti. On these sites, you may find an author's curriculum vitae (C.V.).
You may also search for an author's social media, such as author Venus Bivar's Twitter account @VBivar
Or for news articles, press releases, or publisher biographies that will include the author's information, such as these pages from the publisher Bloomsbury and C-SPAN about Jack R. Censer.