A piston (10, 10') for an internal combustion engine, comprising: an upper crown portion (16, 16') including an upper combustion wall (18, 18') against which combustion forces act and an under-crown surface (60, 60') formed on the undersurface of said upper combustion wall (18, 18'); a lower crown portion (26, 26') including at least one pin boss (36, 38) for coupling to a connecting rod end; an outer cooling gallery (31, 31') formed between said upper crown portion (16, 16') and said lower crown portion (26, 26'); an oil inlet (50, 50') communicating directly with said outer cooling gallery (31, 31') for conducting oil into said outer cooling gallery (31, 31'); an oil outlet (52, 52') spaced from said inlet (50, 50') and communicating directly with said outer cooling gallery (31, 31') for conducting oil out of said outer cooling gallery (31, 31'); and a cooling nozzle (54, 54') communicating directly with said outlet (52, 52') for conducting at least a portion of oil exiting said outer cooling gallery (31, 31') through said outlet (52, 52') and toward said under-crown (60, 60'), wherein said upper crown portion (16, 16') and said lower crown portion (26, 26') are each pre-formed as separate loose-piece members and subsequently joined together as a unitary piston body (12, 12') extending along a common central reciprocating axis (14, 14'), wherein said cooling nozzle (54, 54') has one end (68, 68') attached to an outer gallery floor (48, 48') of the lower crown portion (26, 26'), wherein said outer cooling gallery (31, 31') has a floor (48, 48'), said oil outlet (52, 52') is disposed in said floor (48, 48'); and wherein said cooling nozzle (54, 54') extends between one end (68, 68') adjoining said oil outlet (52, 52') and an opposite end (70, 70') oriented for discharge toward said under-crown (60, 60'), and the piston further including a coupling (69, 69') to which said one end (68, 68') of said cooling nozzle (54, 54') is attached, said coupling (69, 69') being attached to said floor (48, 48') of said outer cooling gallery (31, 31'), and a central cooling gallery directly below at least a portion of said under-crown surface (60, 60'), wherein said central cooling gallery includes an inner gallery floor having a central opening therein; said cooling nozzle (54, 54') extending into said central cooling gallery through said central opening. an upper crown portion (16, 16') including an upper combustion wall (18, 18') against which combustion forces act and an under-crown surface (60, 60') formed on the undersurface of said upper combustion wall (18, 18'); a lower crown portion (26, 26') including at least one pin boss (36, 38) for coupling to a connecting rod end; an outer cooling gallery (31, 31') formed between said upper crown portion (16, 16') and said lower crown portion (26, 26'); an oil inlet (50, 50') communicating directly with said outer cooling gallery (31, 31') for conducting oil into said outer cooling gallery (31, 31'); an oil outlet (52, 52') spaced from said inlet (50, 50') and communicating directly with said outer cooling gallery (31, 31') for conducting oil out of said outer cooling gallery (31, 31'); and a cooling nozzle (54, 54') communicating directly with said outlet (52, 52') for conducting at least a portion of oil exiting said outer cooling gallery (31, 31') through said outlet (52, 52') and toward said under-crown (60, 60'), wherein said upper crown portion (16, 16') and said lower crown portion (26, 26') are each pre-formed as separate loose-piece members and subsequently joined together as a unitary piston body (12, 12') extending along a common central reciprocating axis (14, 14'), wherein said cooling nozzle (54, 54') has one end (68, 68') attached to an outer gallery floor (48, 48') of the lower crown portion (26, 26'), wherein said outer cooling gallery (31, 31') has a floor (48, 48'), said oil outlet (52, 52') is disposed in said floor (48, 48'); and wherein said cooling nozzle (54, 54') extends between one end (68, 68') adjoining said oil outlet (52, 52') and an opposite end (70, 70') oriented for discharge toward said under-crown (60, 60'), and the piston further including a coupling (69, 69') to which said one end (68, 68') of said cooling nozzle (54, 54') is attached, said coupling (69, 69') being attached to said floor (48, 48') of said outer cooling gallery (31, 31'), and a central cooling gallery directly below at least a portion of said under-crown surface (60, 60'), wherein said central cooling gallery includes an inner gallery floor having a central opening therein; said cooling nozzle (54, 54') extending into said central cooling gallery through said central opening.