Psychologism is a philosophical position, according to which psychology plays a central role in grounding or explaining some other, non-psychological type of fact or law. John Locke seems an eminent philosopher explicitly argued for it according to reference here:
The Oxford English Dictionary defines psychologism as: "The view or doctrine that a theory of psychology or ideas forms the basis of an account of metaphysics, epistemology, or meaning; (sometimes) spec. the explanation or derivation of mathematical or logical laws in terms of psychological facts." Psychologism in epistemology, the idea that its problems "can be solved satisfactorily by the psychological study of the development of mental processes", was argued in John Locke's An Essay Concerning Human Understanding (1690).
Apparently to ground mathematical or logical laws in terms of psychological facts sounds wild so most philosophers hold anti-psychologism views. In modern times Blockhead is the name of a theoretical computer system invented as part of a thought experiment by philosopher Ned Block (appeared in a paper titled "Psychologism and Behaviorism" in 1981) to argue for psychologism according to reference here:
In "Psychologism and Behaviorism," Block argues that the internal mechanism of a system is important in determining whether that system is intelligent and claims to show that a non-intelligent system could pass the Turing test... Block says that this does not show that there is only one correct internal structure for generating intelligence but simply that some internal structures do not generate intelligence. The argument is related to John Searle's Chinese room.
However, there're many criticisms against Block's view such as referenced here and it's not a commonly hold view within metaphysics, epistemology and phil. of language.