Sanchez del Amo, 39, steps into the hot seat for the first time as a senior coach, a day after Fernandez was relieved of his duties following Deportivo's 1-1 draw with Cordoba on Wednesday.
Deportivo are fourth-from-bottom in the La Liga standings, two points above the relegation zone with eight matches remaining and Sanchez del Amo will be tasked with preserving the club's top-flight status, starting against Real Sociedad on Saturday.
Sanchez del Amo is no stranger to Deportivo, having helped the club win the league title in 2000 and Copa del Rey in 2002 as a midfielder.
"I would like to thank the president for making it possible that this city, and this club – both important parts of my career as a player, can now be a vital part of my career as a coach," Sanchez del Amo said.
"I will be making my managerial debut with Depor in the Primera Division. It's a dream come true."
Deportivo president Tino Fernandez added: "Victor was part of the legendary Depor side and for all that he achieved as a player, he really needs no introduction.
"I would like to thank Victor for showing faith in this project; I encourage him to succeed and wish the very best of luck in this new venture."
