LeBron James had his best record in a season in 2008-09, with a record of 66-15.

lebron james record win loss record by year

NAME	REC	SEASON	TM	GP	W%	MPG	PPG	RPG	APG	SPG	BPG	TPG	FGM	FGA	FG%	3PM	3PA	3P%	FTM	FTA	FT%	MIN	PTS	REB	AST	STL	BLK	TOV	PF	+/-
LeBron James	66-15	2008-09	CLE	81	.815	37.7	28.4	7.6	7.2	1.7	1.1	3.0	9.7	19.9	48.9	1.6	4.7	34.4	7.3	9.4	78.0	3,054	2,304	613	587	137	93	241	139	+870
LeBron James	61-15	2012-13	MIA	76	.803	37.9	26.8	8.0	7.3	1.7	0.9	3.0	10.1	17.8	56.5	1.4	3.3	40.6	5.3	7.0	75.3	2,877	2,036	610	551	129	67	226	110	+720
LeBron James	60-16	2009-10	CLE	76	.789	39.0	29.7	7.3	8.6	1.6	1.0	3.4	10.1	20.1	50.3	1.7	5.1	33.3	7.8	10.2	76.7	2,966	2,258	554	651	125	77	261	119	+648
LeBron James	50-17	2019-20	LAL	67	.746	34.6	25.3	7.8	10.2	1.2	0.5	3.9	9.6	19.4	49.3	2.2	6.3	34.8	3.9	5.7	69.3	2,316	1,698	525	684	78	36	261	118	+441
LeBron James	56-20	2015-16	CLE	76	.737	35.6	25.3	7.4	6.8	1.4	0.6	3.3	9.7	18.6	52.0	1.1	3.7	30.9	4.7	6.5	73.1	2,709	1,920	565	514	104	49	249	143	+618
LeBron James	45-17	2011-12	MIA	62	.726	37.5	27.1	7.9	6.2	1.9	0.8	3.4	10.0	18.9	53.1	0.9	2.4	36.2	6.2	8.1	77.1	2,326	1,683	492	387	115	50	213	96	+473
LeBron James	50-19	2014-15	CLE	69	.725	36.1	25.3	6.0	7.4	1.6	0.7	3.9	9.0	18.5	48.8	1.7	4.9	35.4	5.4	7.7	71.0	2,493	1,743	416	511	109	49	272	135	+539
LeBron James	57-22	2010-11	MIA	79	.722	38.8	26.7	7.5	7.0	1.6	0.6	3.6	9.6	18.8	51.0	1.2	3.5	33.0	6.4	8.4	75.9	3,063	2,111	590	554	124	50	284	163	+619
LeBron James	51-23	2016-17	CLE	74	.689	37.8	26.4	8.6	8.7	1.2	0.6	4.1	9.9	18.2	54.8	1.7	4.6	36.3	4.8	7.2	67.4	2,795	1,954	639	646	92	44	303	134	+483
LeBron James	52-25	2013-14	MIA	77	.675	37.7	27.1	6.9	6.3	1.6	0.3	3.5	10.0	17.6	56.7	1.5	4.0	37.9	5.7	7.6	75.0	2,902	2,089	533	488	121	26	270	126	+410
LeBron James	30-15	2020-21	LAL	45	.667	33.4	25.0	7.7	7.8	1.1	0.6	3.7	9.4	18.3	51.3	2.3	6.3	36.5	4.0	5.7	69.8	1,504	1,126	346	350	48	25	168	70	+287
LeBron James	50-32	2017-18	CLE	82	.610	36.9	27.5	8.6	9.1	1.4	0.9	4.2	10.5	19.3	54.2	1.8	5.0	36.7	4.7	6.5	73.1	3,026	2,251	709	747	116	71	347	136	+104
LeBron James	47-31	2006-07	CLE	78	.603	40.9	27.3	6.7	6.0	1.6	0.7	3.2	9.9	20.8	47.6	1.3	4.0	31.9	6.3	9.0	69.8	3,190	2,132	526	470	125	55	250	171	+377
LeBron James	45-30	2007-08	CLE	75	.600	40.4	30.0	7.9	7.2	1.8	1.1	3.4	10.6	21.9	48.4	1.5	4.8	31.5	7.3	10.3	71.2	3,027	2,250	592	539	138	81	255	165	+139
LeBron James	47-32	2005-06	CLE	79	.595	42.5	31.4	7.0	6.6	1.6	0.8	3.3	11.1	23.1	48.0	1.6	4.8	33.5	7.6	10.3	73.8	3,361	2,478	556	521	123	66	260	181	+275
LeBron James	41-30	2023-24	LAL	71	.577	35.3	25.7	7.3	8.3	1.3	0.5	3.5	9.6	17.9	54.0	2.1	5.1	41.0	4.3	5.7	75.0	2,504	1,822	518	589	89	38	245	78	+220
LeBron James	30-25	2022-23	LAL	55	.545	35.5	28.9	8.3	6.8	0.9	0.6	3.2	11.1	22.2	50.0	2.2	6.9	32.1	4.6	5.9	76.8	1,954	1,590	457	375	50	32	178	88	+214
LeBron James	41-39	2004-05	CLE	80	.513	42.4	27.2	7.4	7.2	2.2	0.7	3.3	9.9	21.1	47.2	1.4	3.9	35.1	6.0	8.0	75.0	3,388	2,175	588	577	177	52	262	146	+152
LeBron James	28-27	2018-19	LAL	55	.509	35.2	27.4	8.5	8.3	1.3	0.6	3.6	10.1	19.9	51.0	2.0	5.9	33.9	5.1	7.6	66.5	1,937	1,505	465	454	72	33	197	94	+115
LeBron James	25-31	2021-22	LAL	56	.446	37.2	30.3	8.2	6.2	1.3	1.1	3.5	11.4	21.8	52.4	2.9	8.0	35.9	4.5	6.0	75.6	2,084	1,695	459	349	73	59	196	121	-117
LeBron James	33-46	2003-04	CLE	79	.418	39.5	20.9	5.5	5.9	1.6	0.7	3.5	7.9	18.9	41.7	0.8	2.7	29.0	4.4	5.8	75.4	3,122	1,654	432	465	130	58	273	149	-144