Riffing off the thread
I thought it’d be interesting to ask about first initial people. I thought of a few early ones:
F Scott Fitzgerald b.1896
W Somerset Maugham b.1874
J Pierpont Morgan b.1837
The last one is somewhat iffy. His Wikipedia page is J. P. Morgan, but it also says he prefered to go by Pierpont rather than John.
Anyway, any other early F.I. people?
L. Frank Baum b. 1856
J. Paul Getty b. 1892
C. Montgomery Burns - 1881
A. Philip Randolph b. 1889
R Lee Ermey = Ronald Lee Ermey, USMC. Gunny Ermey! Okay, only 1944. 
In Palmdale CA on 10 November 2023, at 1110 hours, an eastbound stretch of Avenue N east of El Camino Sierra was officially opened as the R. Lee Ermey Musical Highway. By driving over the grooved pavement at 45 mph, the road will play 30 seconds of the Marine Corps Hymn.
Its geographical coordinates are given here: ▲ 34.6312, -118.1476.
You made that up!
No, that’s actually very cool. 
Good ones, Q.Q.
Thinking about it, J.P. Morgan may be the earliest double-barrel initial person. That is, a FI - MI - Lastname person.
J. Edgar Hoover b. 1895
T. Rowe Price b. 1898
L. Ron Hubbard b. 1911
A. Aubrey Bodine - 1906
Writer Thomas Coraghessan Boyle (1948, so not a contestant) went by “T Coraghessan Boyle” for quite a while, though it seems to have diminished to TC Boyle in the last couple of decades.
ETA C Everett Koop, 1916.
Hey, how about H Rider Haggard, 1856?
Damn, he was born a month after L. Frank Baum. That Haggard is a laggard.
C. Thomas Howell 1966
J. Robert Oppenheimer, 1904
T. Woodrow Wilson, 1856
Don’t think this one counts, since he’s pretty universally known as just Woodrow Wilson with no initial.
J.G. Wentworth 877 CASH NOW
G. Gordon Liddy
H. Norman Schwarzkopf
M. Night Shymalan
F. Murray Abraham
F. Lee Bailey
P. Diddy Combs
S. Grover Cleveland. 1837 
E. Pluribus Unum
S. Epatha Merkerson
M. Emmet Walsh