Walter Johnson has won the most career games by a pitcher 30 or younger, with 272 wins.

Interpreted as:

most regular-season wins by player age 30 or younger

	NAME	W	L	W%	G	GS	ERA	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	H/9
1	Walter Johnson W. Johnson	272	168	.618	491	398	0.96	2,408	350	77	20	3692.1	2,814		995	30	752	136	88			122	5.87	1.83	3.20	0.07		5.2	0.97	.252	2.43	6.86
2	Catfish Hunter C. Hunter	202	142	.587	439	416	3.10	1,874	167	40	1	3090.0	2,598	1,064	1,180	314	838	44	5	54	12,511	43	5.46	2.44	2.24	0.91	15.0	6.7	1.11	.242	3.44	7.57
3	Bob Feller B. Feller	192	112	.632	384	329	3.05	2,108	213	34	20	2682.0	2,159	910	1,015	125	1,330	38	42		11,292	62	7.07	4.46	1.58	0.42	18.7	11.8	1.30	.264	3.41	7.24
4	Hal Newhouser H. Newhouser	191	140	.577	431	353	3.02	1,708	204	33	18	2784.1	2,482	934	1,099	119	1,177	17	61		11,772	60	5.52	3.80	1.45	0.38	14.5	10.0	1.31	.270	3.55	8.02
5	Wes Ferrell W. Ferrell	190	125	.603	366	317	4.03	966	225	17	13	2583.2	2,816	1,156	1,363	129	1,011	21	41		11,392	33	3.36	3.52	0.96	0.45	8.5	8.9	1.48	.290	4.75	9.81
6	Grover Alexander G. Alexander	190	88	.683	329	277	1.81	1,408	220	61	16	2488.1	2,101		788	46	555	52	47			20	5.09	2.01	2.54	0.17		5.6	1.07	.262	2.85	7.60
7	Robin Roberts R. Roberts	189	142	.571	398	352	3.26	1,433	217	30	23	2858.0	2,714	1,035	1,144	288	574	31	38		11,660	22	4.51	1.81	2.50	0.91	12.3	4.9	1.15	.260	3.60	8.55
8	Don Drysdale D. Drysdale	185	144	.562	459	406	2.98	2,226	152	39	6	3011.2	2,693	998	1,148	249	758	138	34	101	12,395	74	6.65	2.27	2.94	0.74	18.0	6.1	1.15	.271	3.43	8.05
9	Jim Palmer J. Palmer	174	93	.652	347	321	2.61	1,529	146	42	3	2504.2	2,038	727	815	173	853	25	10	32	10,180	64	5.49	3.07	1.79	0.62	15.0	8.4	1.15	.245	2.93	7.32
10	Waite Hoyt W. Hoyt	173	117	.597	423	315	3.60	806	174	19	34	2609.0	2,784	1,043	1,223	101	748	35	87		11,156	29	2.78	2.58	1.08	0.35	7.2	6.7	1.35	.283	4.22	9.60
11	CC Sabathia	171	92	.650	343	343	3.51	1,921	32	12	0	2280.2	2,084	889	971	193	702	71	0	30	9,434	45	7.58	2.77	2.74	0.76	20.4	7.4	1.22	.289	3.83	8.22
12	Mel Harder M. Harder	171	136	.557	450	311	3.83	909	139	16	23	2578.0	2,845	1,098	1,321	121	788	49	92		11,221	24	3.17	2.75	1.15	0.42	8.1	7.0	1.41	.291	4.61	9.93
13	Juan Marichal J. Marichal	170	77	.688	291	284	2.63	1,634	170	37	2	2250.0	1,917	658	771	208	449	24	7	50	9,037	32	6.54	1.80	3.64	0.83	18.1	5.0	1.05	.254	3.08	7.67
14	Tom Seaver T. Seaver	168	96	.636	319	314	2.46	2,099	148	34	1	2447.2	1,940	669	733	173	656	44	5	53	9,760	55	7.72	2.41	3.20	0.64	21.5	6.7	1.06	.260	2.70	7.13
15	Bert Blyleven B. Blyleven	167	148	.530	407	402	2.95	2,357	159	42	0	3000.2	2,699	984	1,103	215	810	75	3	49	12,274	66	7.07	2.43	2.91	0.64	19.2	6.6	1.17	.282	3.31	8.10
16	Greg Maddux G. Maddux	166	105	.613	339	335	2.85	1,660	75	21	0	2386.2	2,119	757	873	119	591	63	3	95	9,719	41	6.26	2.23	2.81	0.45	17.1	6.1	1.14	.274	3.29	7.99
17	Vida Blue V. Blue	165	115	.589	360	349	3.13	1,697	131	33	2	2574.2	2,257	895	1,010	181	832	19	2	45	10,568	72	5.93	2.91	2.04	0.63	16.1	7.9	1.20	.265	3.53	7.89
18	Ken Holtzman K. Holtzman	165	135	.550	382	370	3.32	1,504	124	29	1	2607.0	2,467	961	1,100	215	789	41	4	56	10,889	84	5.19	2.72	1.91	0.74	13.8	7.2	1.25	.270	3.80	8.52
19	Dave McNally D. McNally	165	103	.616	373	347	3.14	1,366	107	29	1	2393.2	2,140	834	908	203	709	60	6	44	9,797	52	5.14	2.67	1.93	0.76	13.9	7.2	1.19	.260	3.41	8.05
20	Sandy Koufax S. Koufax	165	87	.655	397	314	2.76	2,396	137	40	9	2324.1	1,754	713	806	204	817	18	44	48	9,497	87	9.28	3.16	2.93	0.79	25.2	8.6	1.11	.256	3.12	6.79
21	Lefty Gomez L. Gomez	165	89	.650	322	278	3.24	1,337	163	26	10	2233.2	2,030	803	948	123	904	17	28		9,487	30	5.39	3.64	1.48	0.50	14.1	9.5	1.31	.268	3.82	8.18
22	Wilbur Cooper W. Cooper	165	126	.567	392	296	2.61	1,054	212	28	13	2633.2	2,447		989	55	649	77	72			39	3.60	2.22	1.62	0.19		6.0	1.18	.267	3.38	8.36
23	Roger Clemens R. Clemens	161	79	.671	292	291	2.83	1,994	91	35	0	2164.0	1,816	680	759	137	590	58	0	38	8,772	49	8.29	2.45	3.38	0.57	22.7	6.7	1.11	.280	3.16	7.55
24	George Uhle G. Uhle	161	129	.555	380	296	3.92	860	189	17	16	2428.1	2,689		1,262	65	760	98	61		10,658	43	3.19	2.82	1.13	0.24	8.1	7.1	1.42	.296	4.68	9.97
25	Dwight Gooden D. Gooden	157	85	.649	305	303	3.10	1,875	67	23	1	2169.2	1,898	747	823	123	651	41	1	31	8,898	47	7.78	2.70	2.88	0.51	21.1	7.3	1.17	.286	3.41	7.87