Joe Mazzulla has the best winning percentage by a coach when winning 100+ games, winning 73.8 percent of the time.

highest win percentage by an nba coach with at least 100 wins

COACH	W%	W	GP	MPG	PPG	RPG	APG	SPG	BPG	TPG	FGM	FGA	FG%	3PM	3PA	3P%	FTM	FTA	FT%	MIN	PTS	REB	AST	STL	BLK	TOV	PF
Joe Mazzulla	.738	121	164	242.7	119.3	45.8	26.8	6.6	5.9	12.0	43.1	89.5	48.1	16.3	42.5	38.2	16.9	20.9	80.9	39,810	19,558	7,516	4,393	1,078	968	1,967	2,868
Phil Jackson	.704	1,155	1,640	241.8	103.1	43.7	24.1	8.4	5.0	13.6	39.5	83.7	47.2	5.1	14.4	35.6	19.0	25.7	73.7	396,550	169,073	71,619	39,569	13,721	8,254	22,328	35,442
Billy Cunningham	.698	454	650	242.0	111.2	45.6					43.3			0.4			24.2	31.7	76.2	157,325	72,272	29,652					16,236
Larry Bird	.687	147	214	241.4	97.7	40.7	22.2	7.1	4.7	13.2	36.0	78.2	46.0	6.0	15.5	38.6	19.8	25.1	78.9	51,660	20,913	8,702	4,751	1,520	1,013	2,829	4,727
K.C. Jones	.674	522	774	241.9	109.0						43.5			1.9	5.4	34.5	20.7	26.7	77.6	187,210	84,349						17,404
Red Auerbach	.661	938	1,419	241.6	103.0						38.9						25.2			342,835	146,160
Steve Kerr	.654	519	793	241.3	114.1	44.8	28.6	8.2	5.5	14.5	42.2	88.1	47.9	13.2	34.5	38.1	16.5	21.0	78.6	191,345	90,505	35,553	22,652	6,517	4,399	11,483	16,186
Pat Riley	.636	1,210	1,904	241.5	102.5	43.0	24.8				39.6	82.4	48.0	3.9			19.5	26.1	74.7	459,910	195,149	81,888	47,314				44,062
Harold Olsen	.633	100	158	241.6	78.7						30.4						17.8			38,170	12,429
Gregg Popovich	.628	1,388	2,209	241.6	101.6	43.1	23.2	7.3	5.5	13.3	38.3	82.1	46.7	7.6	20.5	36.9	17.4	23.2	75.1	533,785	224,450	95,232	51,174	16,105	12,249	29,434	42,288
Les Harrison	.620	295	476	243.7	84.9						29.9						25.1	34.3	72.9	116,015	40,409
Tom Heinsohn	.619	427	690	241.1	110.6						44.5						21.5	27.7	77.8	166,375	76,314						16,982
Mike Brown	.607	441	727	242.1	103.0	43.5	22.4	7.1	4.6	13.2	38.1	82.4	46.2	8.4	23.1	36.2	18.4	24.9	73.8	176,005	74,853	31,615	16,288	5,136	3,329	9,619	14,584
Mike Budenholzer	.604	484	801	241.3	110.0	45.3	25.1	7.9	4.9	14.1	40.5	87.0	46.6	11.9	32.9	36.3	17.0	22.2	76.4	193,265	88,115	36,262	20,070	6,351	3,915	11,263	14,959
Jerry Sloan	.603	1,221	2,024	241.6	101.3	41.8	25.2	8.2	5.3		37.9	79.0	48.0	3.1	9.0	34.8	22.4	29.4	76.3	488,910	205,077	84,581	51,046	16,672	10,714		48,925
Danny Ainge	.602	136	226	242.4	100.2	41.3	25.5	8.8	4.7	14.2	37.9	81.6	46.5	5.7	15.4	36.8	18.7	24.7	75.7	54,790	22,652	9,325	5,766	1,992	1,056	3,218	4,810
Chuck Daly	.593	638	1,075	241.6	105.3	45.1	24.4		5.1		41.0	87.2	47.1	1.6	5.2	30.7	21.6	28.4	76.0	259,725	113,168	48,516	26,209		5,468		25,033
Tyronn Lue	.590	312	529	241.1	111.7	43.4	23.9	7.1	4.3	12.9	40.8	86.1	47.4	12.7	33.2	38.2	17.3	21.9	79.0	127,560	59,065	22,966	12,635	3,769	2,290	6,843	10,008
Jerry West	.589	145	246	241.4	110.0	45.1	26.9				45.6	92.4	49.4				18.8	24.9	75.4	59,390	27,067	11,089	6,613				5,683
Larry Costello	.589	430	730	241.1	109.1						44.8						19.5	26.1	74.8	176,000	79,624
George Karl	.588	1,175	1,999	241.6	104.8	42.1	23.7	9.1	5.0	14.8	39.3	83.3	47.1	5.4	14.9	36.0	20.9	27.7	75.6	483,035	209,431	84,105	47,422	18,189	9,952	29,663	46,119
Doc Rivers	.587	1,113	1,895	241.8	103.7	42.0	22.8	8.0	4.9	13.9	38.2	81.9	46.6	8.0	21.9	36.8	19.3	25.4	76.0	458,150	196,512	79,603	43,197	15,076	9,294	26,395	41,555
Erik Spoelstra	.587	750	1,277	241.9	103.5	41.8	22.5	7.7	4.8	13.3	38.3	82.0	46.7	9.5	26.2	36.1	17.5	22.9	76.4	308,955	132,227	53,435	28,790	9,851	6,164	16,948	25,143
John Kundla	.583	423	725	242.2	91.5						33.4						24.7	33.0	74.8	175,625	66,340
Rick Adelman	.582	1,042	1,791	242.0	104.0	44.0	23.6	8.4	4.6	14.5	39.0	85.4	45.7	5.8	16.4	35.2	20.2	26.6	76.1	433,440	186,184	78,849	42,238	15,057	8,282	25,962	37,464