LeBron James has the most career All-NBA team selections by a player younger than 25, with 6 selections.

Interpreted as:

player with most all NBA 1st teams under 25 years old

NAME	ALLNBA	GP	MPG	PPG	RPG	APG	SPG	BPG	FGM	FGA	FG%	3PM	3PA	3P%	FTM	FTA	FT%	TS%	OREB	DREB	TPG	MIN	PTS	REB	AST	STL	BLK	TOV	PF	+/-
LeBron James	6	505	40.4	27.6	7.0	6.8	1.7	0.9	9.9	20.9	47.2	1.4	4.2	33.0	6.5	8.8	74.0	55.8	1.3	5.7	3.3	20,402	13,927	3,537	3,419	879	432	1,663	1,011	+1927
Dwight Howard	5	508	35.7	17.6	12.6	1.5	0.9	2.1	6.2	10.7	57.5	0.0	0.0	5.0	5.2	8.8	59.6	60.2	3.6	9.1	3.0	18,130	8,936	6,419	745	461	1,088	1,540	1,650	+1731
Kobe Bryant	5	496	33.9	21.5	5.0	4.2	1.4	0.6	7.7	16.8	45.6	0.8	2.5	33.2	5.3	6.4	83.1	54.8	1.2	3.7	2.7	16,826	10,658	2,458	2,060	714	320	1,339	1,323	+2020
Luka Doncic	4	380	34.7	28.5	8.6	8.2	1.2	0.5	9.7	20.6	47.0	2.9	8.5	34.5	6.2	8.3	74.5	58.7	1.0	7.6	4.0	13,192	10,825	3,264	3,110	443	175	1,509	855	+712
Giannis Antetokounmpo	4	487	32.7	19.4	8.5	4.2	1.2	1.3	7.1	13.5	52.4	0.5	1.9	28.2	4.7	6.4	73.0	59.3	1.7	6.8	2.7	15,917	9,427	4,135	2,042	589	656	1,313	1,465	+760
Kevin Durant	4	461	38.2	26.6	6.8	3.1	1.3	1.0	9.0	18.9	47.5	1.5	4.1	37.3	7.2	8.1	88.4	59.3	0.9	6.0	3.2	17,595	12,258	3,153	1,447	578	470	1,474	862	+640
Tim Duncan	4	288	38.9	22.1	12.0	2.9	0.8	2.4	8.5	16.7	50.9	0.0	0.2	16.4	5.0	7.3	68.1	55.3	3.3	8.7	3.2	11,216	6,351	3,463	824	236	689	909	858	+1967
Tracy McGrady	4	487	33.6	21.4	6.4	4.1	1.3	1.2	7.8	17.4	44.7	1.1	3.2	35.4	4.7	6.2	75.6	53.0	2.0	4.4	2.2	16,375	10,420	3,115	2,007	643	570	1,067	965	+169
Shaquille O'Neal	4	341	38.0	27.0	12.6	2.5	0.8	2.8	10.9	18.8	57.8	0.0	0.0	7.1	5.3	9.9	53.6	58.4	4.1	8.4	3.0	12,941	9,208	4,282	859	283	964	1,022	1,219	+220
Isiah Thomas	4	393	36.7	20.8	3.8	10.3			7.9	17.1	46.2	0.3			4.6	6.2	74.9	52.4				14,410	8,156	1,502	4,066				1,427
Oscar Robertson	4	249		29.6					10.5						8.5	10.5	81.6						7,363						850
Bob Pettit	4	238		23.9					8.3						7.3	9.7	75.3						5,684						727
Dolph Schayes	4	264		16.4					5.0						6.4	8.1	79.4						4,322
Max Zaslofsky	4	253		17.4					6.3						4.7								4,406
Jayson Tatum	3	424	33.9	22.2	6.9	3.3	1.1	0.7	7.8	17.1	45.7	2.4	6.4	37.7	4.2	5.0	84.8	57.7	0.9	6.0	2.3	14,385	9,429	2,936	1,386	470	297	954	894	+2404
Anthony Davis	3	393	34.6	23.2	10.3	1.8	1.3	2.4	8.8	16.9	51.7	0.3	1.0	31.3	5.4	6.8	79.4	58.3	2.5	7.8	1.8	13,612	9,125	4,044	725	522	925	719	937	+35
Blake Griffin	3	295	35.6	21.3	10.2	3.6	1.0	0.6	8.3	15.6	53.0	0.1	0.4	23.4	4.6	7.3	63.4	56.5	2.8	7.4	2.5	10,516	6,286	3,015	1,063	291	179	749	926	+1044
Russell Westbrook	3	398	34.3	19.9	4.8	6.9	1.6	0.3	7.1	16.4	43.1	0.6	2.1	30.2	5.1	6.3	81.3	51.9	1.6	3.2	3.5	13,646	7,908	1,922	2,741	637	125	1,388	949	+1116
Carmelo Anthony	3	445	36.2	24.2	6.1	3.1	1.1	0.4	8.7	18.9	46.0	0.7	2.3	30.7	6.1	7.7	79.6	54.3	2.0	4.2	3.1	16,113	10,768	2,730	1,367	503	199	1,375	1,334	+790
Dwyane Wade	3	244	37.7	23.6	5.0	6.3	1.7	0.9	8.1	16.9	48.1	0.2	0.9	25.0	7.1	9.1	77.6	56.4	1.3	3.6	3.7	9,188	5,751	1,214	1,545	413	212	914	666	+1001
Amar'e Stoudemire	3	308	33.7	19.8	9.0	1.2	0.9	1.4	7.1	13.6	52.5	0.0	0.1	15.4	5.5	7.6	72.7	58.5	2.8	6.2	2.6	10,378	6,108	2,771	378	288	434	798	1,057	+973
Gilbert Arenas	3	376	37.3	22.5	4.2	5.5	1.8	0.2	7.3	17.0	43.2	2.1	5.6	36.8	5.7	7.1	80.3	55.9	1.0	3.2	3.4	14,026	8,445	1,576	2,068	663	91	1,271	1,194	+92
Dirk Nowitzki	3	367	35.5	20.1	8.2	2.3	1.0	1.0	6.9	14.8	46.5	1.5	4.1	37.8	4.8	5.7	84.8	58.1	1.3	6.9	1.8	13,029	7,394	2,994	848	365	355	667	1,034	+1796
Kevin Garnett	3	448	37.4	18.5	9.5	3.9	1.4	1.8	7.6	15.7	48.7	0.2	0.5	31.0	3.0	4.1	74.6	52.8	2.7	6.9	2.5	16,735	8,280	4,271	1,733	639	798	1,110	1,173	+869
Kevin Johnson	3	291	34.0	18.1	3.5	9.7	1.6	0.2	6.3	12.8	49.6	0.1	0.4	17.5	5.4	6.3	85.5	58.3	0.6	2.9	3.2	9,880	5,278	1,010	2,823	461	69	928	650