Fundamental motor skills (FMSs) are building blocks for future movements and may vary according to cultural context. Moreover, network analysis can identify which skills contribute most to an overall set of skills. This study identified the most influential FMS in samples of U.S. and Brazil preschoolers that may contribute to a pattern of adequate motor skills. Participants were 101 Brazilian (55 boys; 47.52 ± 5.57 months of age) and 236 U.S. preschoolers (108 boys; 49.56 ± 8.27 months of age), who provided completed FMS assessments (Test of Gross Motor Development—third edition). Confirmatory factorial analysis was used to test alternative models. To quantify the importance of each variable in the network, the expected influence was calculated, using the network analysis Mplus, Rstudio, and JASP (version 0.14.1). Reduced models with nine and 11 FMS for Brazilian and U.S. preschoolers, respectively, showed adequate adjustment indexes. Jump (1.412) and one-hand strike (0.982) in the Brazilian sample, and hop (1.927) and dribble (0.858) in the U.S. sample, showed the highest expected influence values. This study presents a new perspective to report which are the most important FMS in preschoolers of different sociocultural contexts, which act as building blocks for the acquisition of more complex motor skills.