Let’s just cut to the chase. It’s lazh-uh-way, with the emphasis on the first syllable.
It’s not lah-zhwa, with the accent on the second syllable, though this is the correct French pronunciation. And certainly there are other people named Lajoie who pronounce it that way.
It’s not luh-joy, with a hard J and the accent on the second syllable. However there are a number of Lajoies who pronounce it that way. For example, Bill Lajoie, who played minor league baseball and later became a successful baseball executive, used that pronunciation. (By the way, some sources state that Bill was the grandson of Nap, but this is not true. Nap’s only daughter, Lillian, had no children.) And two-time NASCAR Busch Series champion Randy LaJoie (and his sons Cory and Casey) use this pronunciation, as well. In fact, you can hear Randy pronounce his name in this video.
So why do we know that the correct pronunciation is lazh-uh-way? Because the overwhelming preponderance of contemporary evidence clearly says so.
Library of Congress, Prints & Photographs Division, LC-DIG-hec-02789
Absent an audio recording of Nap Lajoie reciting his own name, the best method to determine the correct way to say his last name is to scour contemporary accounts for direct references. Doing that research reveals that the vast majority of newspaper accounts that address this question give the answer of lazh-uh-way. Additionally, in doing this research, I found a number of articles that very directly and emphatically refute the luh-joy pronunciation.
Below are just a few examples of the many references regarding the correct way to say Lajoie that were published during Nap’s lifetime:
From the Buffalo Commercial, April 28, 1897:
Lashu-aye, with the accent on the first syllable, which is the proper way to pronounce Lajoie’s name, has rather too much of a French twist to it to suit his colleagues on the Philadelphia team, so the players call him “Larry” for short.
From the Nebraska State Journal of September 29, 1901:
Lajoie is pronounced “Lazhoway.” The way he hits is pronounced “Get-out-of-the-way.”
From the Fort Wayne (IN) News of April 21, 1903:
Lajoie’s name is pronounced “Lazh-ah-we,” with the emphasis on the first syllable.
From the Washington Post of August 12, 1906:
In St. Louis and Washington they call him “La-Joe,” in Chicago, Detroit, Philadelphia, and, yes, in Cleveland, it is nearly always “Lo-Joy;” in New York they scorn everything but the nickname, “Larry,” or perhaps they fear to show themselves up on a French word, and pass up his last name for reasons of policy. At any rate, the fact remains that in Boston only is his name pronounced aright among the hoi polloi, “Lazhooay.”
From the St. Louis Star and Times of January 2, 1912
How is Lajoie pronounced? As though spelled “Lash-way.”
From the Elyria (OH) Chronicle-Telegraph of February 24, 1912
According to Napoleon it can be [pronounced] by running the scales a few times and with some finger practice by going at it thus—Lazh-u-way.
From the Louisville Courier-Journal of January 24, 1937:
Most baseball fans called Napoleon “La-Joy,’ with accent on the “joy.” He pronounces his name “Lazh-a-way,” with accent on the “Lazh,” the “azh” being the same as in “azure.”
From the Muncie (IN) Star Press of April 27, 1945:
His name is pronounced Lasj-o-wee, incidentally, with the “a” like the “a” in cat. The accent is on the last syllable. You thoughts it was La-Joy, didn’t ya.
From the New York Daily News of April 8, 1956:
Baltimore’s Bill Lajoie, the 21-year-old college outfielder, pronounces it La-joy not as old Nap did, Lazhway.
Did I find references suggesting that luh-joy was the correct pronunciation? Yes, but these were very few and far between.
Finally, it appears that Nap himself wasn’t particularly concerned about how people pronounced (or mispronounced) his name. In an interview with the Louisville Courier-Journal published on May 11, 1911, Lajoie was quoted as saying, “A poet would have to have a whole kit of rhymes to get any poetry out of my monaker. Down East they called me Lazhwah. In Cleveland they call me La-zhu-way. Out on the circuit its La-joy. Down here in Alexandria, its Mistah Lah-joh-ee. My wife is the only one I know who knows how to pronounce it. She calls me Larry, sometimes real sharp.”