Since 1900, Dutch Leonard has the best ERA in a season, with an ERA of 0.96 in 1914.

Interpreted as:

best era with a minimum of 1 IP per team game by a player in a season in the modern era

	NAME	ERA	SEASON	TM	G	W	L	W%	GS	SO	CG	SHO	SV	IP	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	ERA-	FIP	FIP-	H/9	PRAA
1	Dutch Leonard D. Leonard	0.96	1914	BSA	36	19	5	.792	25	176	17	7	3	224.2	139	24	34	3	60	8	8		842	2	7.05	2.40	2.93	0.12	20.9	7.1	0.89	.229	1.36	36	1.95	70	5.57	20.4
2	Mordecai Brown M. Brown	1.04	1906	CHC	36	26	6	.813	32	144	27	9	3	277.1	198	32	56	1	61	4	4		1,044	2	4.67	1.98	2.36	0.03	13.8	5.8	0.93	.236	1.82	39	2.08	75	6.43	21.1
3	Yoshinobu Yamamoto Y. Yamamoto	1.06	2025	LAD	6	3	2	.600	6	43	0	0	0	34.0	23	4	7	2	11	0	0	0	132	1	11.38	2.91	3.91	0.53	32.6	8.3	1.00	.276	1.85	26	2.27	56	6.09	6.6
4	Bob Gibson B. Gibson	1.12	1968	STL	34	22	9	.710	34	268	28	13	0	304.2	198	38	49	11	62	7	0	6	1,161	4	7.92	1.83	4.32	0.32	23.1	5.3	0.85	.230	1.45	38	1.77	63	5.85	34.8
5	Tyler Mahle T. Mahle	1.14	2025	TEX	6	3	0	1.000	6	26	0	0	0	31.2	18	4	4	0	13	0	0	0	122	0	7.39	3.69	2.00	0.00	21.3	10.7	0.98	.217	1.14	29	2.65	65	5.12	5
6	Christy Mathewson C. Mathewson	1.14	1909	NYG	37	25	6	.806	33	149	26	8	2	275.1	192	35	57	2	36	0	4		998	4	4.87	1.18	4.14	0.07	14.9	3.6	0.83	.234	1.86	44	1.62	61	6.28	31.7
7	Walter Johnson W. Johnson	1.14	1913	WSH	48	36	7	.837	36	243	29	11	2	346.0	232	44	56	9	38	9	10		1,271	2	6.32	0.99	6.39	0.23	19.1	3.0	0.78	.229	1.46	39	1.90	63	6.03	42.3
8	Jack Pfiester J. Pfiester	1.15	1907	CHC	30	14	9	.609	22	90	13	3	0	195.0	143	25	61	1	48	5	5		745	2	4.15	2.22	1.88	0.05	12.1	6.4	0.98	.236	2.82	47	2.14	81	6.60	10.6
9	Addie Joss A. Joss	1.16	1908	CLE	42	24	11	.686	35	130	29	9	2	325.0	232	42	77	2	30	2	6		1,209	6	3.60	0.83	4.33	0.06	10.8	2.5	0.81	.220	2.13	49	1.68	76	6.42	19.3
10	Carl Lundgren C. Lundgren	1.17	1907	CHC	28	18	7	.720	25	84	21	7	0	207.0	130	27	42	0	92	2	3		795	2	3.65	4.00	0.91	0.00	10.6	11.6	1.07	.211	1.83	48	2.73	104	5.65	-2.3
11	Nick Pivetta N. Pivetta	1.20	2025	SDP	5	4	1	.800	5	30	0	0	0	30.0	16	4	4	1	7	0	0	0	111	0	9.00	2.10	4.29	0.30	27.0	6.3	0.77	.205	1.20	31	2.20	56	4.80	5.8
12	Hunter Brown H. Brown	1.22	2025	HOU	6	4	1	.800	6	40	0	0	0	37.0	24	5	6	1	7	0	0	0	134	0	9.73	1.70	5.71	0.24	29.9	5.2	0.84	.267	1.46	32	1.82	46	5.84	8.9
13	Grover Alexander G. Alexander	1.22	1915	PHN	49	31	10	.756	42	241	36	12	3	376.1	253	51	86	3	64	10	7		1,435	2	5.76	1.53	3.77	0.07	16.8	4.5	0.84	.224	2.06	43	1.82	63	6.05	44.1
14	Cy Young C. Young	1.26	1908	BOS	36	21	11	.656	33	150	30	3	2	299.0	230	42	68	1	37	1	3		1,116	4	4.52	1.11	4.05	0.03	13.4	3.3	0.89	.247	2.05	52	1.52	67	6.92	25.4
15	Ed Walsh E. Walsh	1.27	1910	CWS	45	18	20	.474	36	258	33	7	5	369.2	242	52	87	5	61	4	7		1,359	6	6.28	1.49	4.23	0.12	19.0	4.5	0.82	.230	2.12	52	1.63	66	5.89	34.8
16	Walter Johnson W. Johnson	1.27	1918	WSH	39	23	13	.639	29	162	29	8	3	326.0	241	46	71	2	70	8	10		1,261	8	4.47	1.93	2.31	0.06	12.8	5.6	0.95	.235	1.96	47	2.04	74	6.65	25.9
17	Christy Mathewson C. Mathewson	1.28	1905	NYG	43	31	9	.775	37	206	32	8	3	338.2	252	48	85	4	64	1	6		1,294	6	5.47	1.70	3.22	0.11	15.9	4.9	0.93	.243	2.26	42	2.03	69	6.70	34.9
18	Jack Taylor J. Taylor	1.29	1902	CHO	37	23	11	.676	34	88	34	8	1	333.2	273	48	86	2	45	12	3		1,278	10	2.37	1.21	1.96	0.05	6.9	3.5	0.95	.240	2.32	49	2.73	98	7.36	0.6
19	Jack Coombs J. Coombs	1.30	1910	PHA	45	31	9	.775	38	224	35	13	1	353.0	248	51	74	0	115	7	6		1,353	10	5.71	2.93	1.95	0.00	16.6	8.5	1.03	.246	1.89	53	2.09	83	6.32	15.8
20	Mordecai Brown M. Brown	1.31	1909	CHC	50	27	9	.750	34	172	32	8	7	342.2	246	50	78	1	53	7	15		1,280	9	4.52	1.39	3.25	0.03	13.4	4.1	0.87	.234	2.05	51	1.78	68	6.46	32.4
21	Walter Johnson W. Johnson	1.36	1910	WSH	45	25	17	.595	42	313	38	8	1	370.0	262	56	92	1	76	13	3		1,367	21	7.61	1.85	4.12	0.02	22.9	5.6	0.91	.271	2.24	56	1.39	56	6.37	45.2
22	Walter Johnson W. Johnson	1.39	1912	WSH	50	33	12	.733	37	303	34	7	2	369.0	259	57	89	2	76	16	13		1,413	11	7.39	1.85	3.99	0.05	21.4	5.4	0.91	.253	2.17	42	2.03	63	6.32	49.6
23	Mordecai Brown M. Brown	1.39	1907	CHC	34	20	6	.769	27	107	20	6	3	233.0	180	36	51	2	40	6	7		861	4	4.13	1.55	2.68	0.08	12.4	4.6	0.94	.252	1.97	56	1.97	75	6.95	17.2
24	Harry Krause H. Krause	1.39	1909	PHA	32	18	8	.692	21	139	16	7	0	213.0	151	33	49	2	49	13	8		801	2	5.87	2.07	2.84	0.08	17.4	6.1	0.94	.249	2.07	58	1.91	82	6.38	9.5
25	Ed Walsh E. Walsh	1.41	1909	CWS	31	15	11	.577	28	127	20	8	2	230.1	166	36	52	0	50	4	3		871	4	4.96	1.95	2.54	0.00	14.6	5.7	0.94	.241	2.03	61	1.82	81	6.49	10.3