Human genetic studies have pointed to a prominent role for innate immunity and lipid pathways in human immunological and neurodegenerative disorders. Our understanding of the composition and function of immunomodulatory lipid networks in innate immune cells, however, remains incomplete. Here, we show that phospholipase C gamma 2 (PLCγ2 or PLCG2) – mutations in which are associated with autoinflammatory disorders and Alzheimer’s disease – serves as a principal source of diacylglycerol (DAG) pools that are converted into a cascade of bioactive endocannabinoid (eCB) and eicosanoid lipids by DAG lipase (DAGL) and monoacylglycerol lipase (MGLL) enzymes in innate immune cells. We show that this lipid network is tonically stimulated by disease-relevant human mutations in PLCγ2, as well as Fc receptor activation in primary human and mouse macrophages. Genetic disruption of PLCγ2 in mouse microglia suppressed DAGL/MGLL-mediated eCB-eicosanoid crosstalk and also caused widespread transcriptional and proteomic changes, including the reorganization of immune-relevant lipid pathways reflected in reductions in DAGLB and elevations in PLA2G4A. Despite these changes, Plcg2-/- mice showed generally normal pro-inflammatory cytokine responses to lipopolysaccharide treatment, instead displaying a more restricted deficit in microglial activation that included impairments in prostaglandin production and CD68 expression. Our findings enhance the understanding of PLCγ2 function in innate immune cells, delineating a role in crosstalk with endocannabinoid/eicosanoid pathways and modulation of subsets of cellular responses to inflammatory stimuli.