Rick Barry had the most games by a player younger than 23 with 40+ points, with 35 games.

most 40 point games by a player under the age of 23

Interpreted as:

most 40 or more point regular-season games by a player under the age of 23

NAME	GP	PTS	MPG	PPG	RPG	APG	SPG	BPG	TPG	FGM	FGA	FG%	3PM	3PA	3P%	FTM	FTA	FT%	MIN	REB	AST	STL	BLK	TOV	PF	+/-
Rick Barry	35	1,600	44.0	45.7	10.3	4.1				16.3	33.4	48.9				13.0	14.6	89.1	1,541	362	142				124
LeBron James	20	896	44.8	44.8	7.7	7.3	2.1	0.8	3.5	15.8	28.2	56.0	3.0	6.5	46.5	10.3	12.5	82.4	897	153	145	42	15	70	48	+140
Kevin Durant	17	725	42.6	42.6	9.5	3.1	1.3	1.3	3.1	14.2	24.2	58.6	2.8	5.9	47.5	11.5	12.6	90.7	725	161	52	22	22	52	40	+106
Shaquille O'Neal	17	728	41.9	42.8	14.5	1.9	0.8	2.2	2.7	17.3	26.2	65.9	0.0	0.0		8.2	13.6	60.6	713	247	32	14	38	46	45
Trae Young	16	705	39.8	44.1	4.8	9.6	0.9	0.3	5.8	13.3	25.2	52.9	5.4	11.5	47.3	12.0	13.7	87.7	638	77	153	14	4	92	29	+83
Luka Doncic	14	606	38.5	43.3	9.5	9.6	0.9	0.4	4.7	14.5	26.9	53.8	5.1	11.2	45.2	9.2	11.8	78.2	539	133	135	13	6	66	45	+145
Walt Bellamy	12	537		44.8	20.7					17.5						9.8	13.3	73.6		248					46
Tracy McGrady	11	489	42.6	44.5	9.9	4.3	1.5	1.2	3.1	16.6	30.7	54.1	2.2	4.3	51.1	9.0	12.4	72.8	469	109	47	17	13	34	22	+40
Bob McAdoo	11	483		43.9	17.5					17.6	28.1	62.8				8.6	10.5	81.9		192					39
Oscar Robertson	11	474		43.1	11.3	11.3				15.5						12.0	14.5	82.5		124	124				39
Anthony Edwards	10	445	38.5	44.5	5.9	4.3	1.9	1.1	2.9	15.8	27.8	56.8	5.7	11.7	48.7	7.2	9.5	75.8	385	59	43	19	11	29	18	+98
Devin Booker	9	437	40.2	48.6	6.6	6.4	1.3	0.7	4.9	16.6	30.0	55.2	4.1	9.1	45.1	11.3	12.8	88.7	361	59	58	12	6	44	27	+11
Kareem Abdul-Jabbar	9	393		43.7	14.3	3.4				16.3						11.0	14.9	73.9		129	31				24
Cam Thomas	8	347	37.5	43.4	3.6	3.5	0.6	0.3	3.5	14.9	26.6	55.9	5.0	10.3	48.8	8.6	9.4	92.0	300	29	28	5	2	28	23	-1
Jalen Green	7	288	37.0	41.1	4.3	3.4	0.7	0.3	2.1	13.9	23.1	59.9	5.4	10.7	50.7	8.0	9.6	83.6	259	30	24	5	2	15	12	+75
Ja Morant	7	308	36.3	44.0	5.1	6.4	1.4	0.6	3.6	15.3	25.9	59.1	3.3	5.0	65.7	10.1	12.6	80.7	254	36	45	10	4	25	14	+67
Anthony Davis	7	309	42.3	44.1	14.0	3.4	1.1	1.9	2.1	16.3	24.9	65.5	0.9	1.6	54.5	10.7	11.9	90.4	296	98	24	8	13	15	16	+41
Kyrie Irving	7	318	41.7	45.4	4.0	6.0	2.6	0.1	4.0	16.4	29.9	55.0	5.1	8.7	59.0	7.4	7.9	94.5	292	28	42	18	1	28	19	+47
Kobe Bryant	7	310	46.1	44.3	6.4	4.9	1.0	1.6	4.3	15.7	28.7	54.7	1.1	3.3	34.8	11.7	12.7	92.1	323	45	34	7	11	30	20	+10
Michael Jordan	7	307	42.9	43.9	8.6	6.6	2.7	1.1	3.4	16.7	26.6	62.9	0.1	0.6	25.0	10.3	11.4	90.0	300	60	46	19	8	24	28
John Drew	7	290	39.3	41.4	16.1	2.7				14.1	24.6	57.6				13.1	17.3	76.0	275	113	19				29
Andrew Wiggins	6	250	39.8	41.7	3.3	1.8	0.8	0.3	1.7	15.0	26.7	56.3	2.3	5.3	43.8	9.3	11.8	78.9	239	20	11	5	2	10	11	+44
Amar'e Stoudemire	6	262	39.3	43.7	10.7	2.5	1.5	1.5	1.7	15.7	23.8	65.7	0.0	0.3	0.0	12.3	15.8	77.9	236	64	15	9	9	10	21	+55
Carmelo Anthony	6	253	43.4	42.2	7.0	2.3	2.2	1.0	3.7	15.3	27.3	56.1	1.0	2.0	50.0	10.5	12.7	82.9	260	42	14	13	6	22	24	+32
Allen Iverson	6	261	45.7	43.5	4.5	6.5	1.7	0.2	5.2	15.2	29.3	51.7	3.7	8.0	45.8	9.5	13.0	73.1	274	27	39	10	1	31	20	-74