The replisome, the multiprotein system responsible for genome duplication, is a highly dynamic complex, displaying a large number of different enzyme activities. Recently, the Saccharomyces cerevisiae minimal replication reaction has been successfully reconstituted in vitro. This provided an opportunity to uncover the enzymatic activities of many of the components in a eukaryotic system, including DNA polymerases. Their dynamic behavior and interactions in the context of the replisome, however, remain unclear. We use a single-molecule tethered-bead assay to provide real-time visualization of leading-strand synthesis by a reconstituted eukaryotic replisome for the first time. The minimal reconstituted leading-strand replisome requires 24 proteins, forming the CMG helicase, the Pol ε DNA polymerase, the RFC clamp loader, the PCNA sliding clamp, and the RPA single-stranded DNA binding protein. We observe rates and product lengths similar to those obtained from ensemble biochemical experiments. At the single-molecule level, we probe the behavior of the Mrc1–Tof1–Csm3 (MTC) complex, a component of the replication progression complex, and characterize its interaction with active leading-strand polymerases. We show that MTC enhances the rate of the leading-strand replisome threefold. The introduction of periods of fast replication by MTC leads to an average rate enhancement of a factor of two, similar to observations in cellular studies. Surprisingly, however, we observe that the MTC complex acts in a dynamic fashion with the moving replisome, leading to alternating phases of slow and fast replication by Pol ε.