The Uruguayan-born Martinez, who is headed to North Carolina, scored twice for DSC in its 5-1 win over Norcross Fury Gold in Thursday's final. He also scored twice in the semifinals.
His 182 goals in four years at Northwestern rank sixth all-time in U.S. prep history.
North Carolina's South Carolina SA (U-15) and Triangle United (U-17) repeated as regional champions.
CASL Elite won its third U-14 Region III boys championship in the last seven years.
Teams from North Texas were surprisingly shut out in the regional championships.
The Dallas Texans, who produced winners at each of the last four regionals, had three affiliated teams fall in Thursday's finals at Pizza Hut Park in Frisco, Texas.
Their U-16s are headed to next month's National Championships in Lancaster, Mass., as National League champions.
REGION III BOYS
CASL Elite (NC) 0 Dallas Texans Red (TX-N) 0
(CASL Elite wins 3-1 on penalties.)
South Charlotte SA Gold (NC) 1, Tulsa Soccer Club Black (OK) 0, OT
SCSA-Kyle Parker (90+)
CESA Premier (SC) 2, Dallas Texans Red (N-TX) 0
CESA-Ricardo Garbanzo (81, 83)
Triangle United (NC) 4, Lonestar Red (S-TX) 2
TRI-Ezra Ntirugelegwa (45), Sebastian Garner (62, 88), Cristian Alphonso (74); LS-own goal (41), Justin Franz (52).
Discoveries SC Green (SC) 5, Norcross Fury Gold (GA) 1
DSC-George Khoury (14), Enzo Martinez (48, 83), Andrew Gorospe (63), Ralph Lundy (77); NFC-goal scorer unavailable
NASA Elite (GA) 2, Dallas Texans Houston Red (TX-S) 2
(NASA Elite wins 10-9 on penalties.)
NASA-Russell Thompson (44), Mark Lavery (85); DTX-Luis Busto (27), Christopher Deaville (65)