Catalyzes the transfer of the gamma-phospho group of ATP to thymidine to generate dTMP in the salvage pathway of pyrimidine synthesis. The dTMP serves as a substrate for DNA polymerase during viral DNA replication. Allows the virus to be reactivated and to grow in non-proliferative cells lacking a high concentration of phosphorylated nucleic acid precursors. ATP + thymidine = ADP + dTMP + H(+) Homodimer. Localizes to the centrosome and more precisely to the periphery of the centriole, tightly encircling the tubulin-rich centrioles. Phosphorylates and thereby activates certain drugs like acyclovir (ACV), valacyclovir, and famciclovir to a toxic form, that leads to successful suppression of the infection, while the uninfected cell does not have this ability because it lacks TK. Belongs to the herpesviridae thymidine kinase family.