The former Leyton Orient and Cardiff boss replaces Jose Riga, whose second spell in charge ended after Charlton's relegation from the Sky Bet Championship last season.
Slade, who has agreed a three-year contract at The Valley, told the club's official website: " I am very pleased to be appointed manager of Charlton, a club with a fantastic tradition and history
"I was attracted to Charlton as it has has great facilities, passionate fans and a very successful academy
This is a hugely exciting opportunity and I cannot wait to get started."
Slade, 55, moved upstairs at Cardiff to become head of football at the end of the season but soon decided he wanted another managerial role.
His appointment marks a change in policy for controversial owner Roland Duchatelet, who has previously appointed little-known Belgian head coaches such as Riga, Bob Peeters and Karel Fraeye.
Charlton CEO Katrien Meire added: "We're delighted to have agreed terms with Russell.
"We don't underestimate the challenge of getting Charlton back into the Championship
We believe Russell is the man to help us achieve this and, with the help of everyone involved in the club, ensure that Charlton have a successful 2016-17 campaign.
"Russell has vast experience in the division and is a two-time League One Manager of The Year
He joins us as manager on a long-term contract and his appointment represents the start of an exciting new era at the club under his guidance."
Source : PA
Source: PA