Ms. Psaki, 46, will host a show at 9 p.m. Tuesday through Friday, replacing Alex Wagner, a longtime political journalist who has anchored that hour since 2022, according to a memo to staff from Rebecca Kutler, MSNBC’s president. Ms. Wagner will remain at MSNBC as an on-air correspondent.

After Joy Reid’s show, ‘The ReidOut,’ was canceled by the network, MSNBC has moved Jen and other TV hosts to new time slots.

MSNBC confirmed plans to overhaul its daytime, primetime and weekend lineup, with Jen Psaki and the three anchors of The Weekend — Symone Sanders Townsend, Michael Steele and Alicia Menendez — getting primetime shows.