Both players have signed two-year deals from their respective clubs.
Kevin Blackwell said: "I'm sure they will be great assets to the club and bring with them a wealth of Premiership and First Division experience which is crucial.''
The boss also said of 29-year-old Joachim: "He is a proven scorer in the First Division and offers us something we've not had for a while, lightning quick pace. I spoke to Eric Black [former Coventry boss] about him and he said Julian was one of the reasons Coventry did as well as they did last season.
"He had a strong finish to the season and we'll just be happy for him to carry on where he left off."
Kevin Blackwell said: "I'm sure they will be great assets to the club and bring with them a wealth of Premiership and First Division experience which is crucial.''
The boss also said of 29-year-old Joachim: "He is a proven scorer in the First Division and offers us something we've not had for a while, lightning quick pace. I spoke to Eric Black [former Coventry boss] about him and he said Julian was one of the reasons Coventry did as well as they did last season.
"He had a strong finish to the season and we'll just be happy for him to carry on where he left off."
Butler was offered only a 12-month extension to his contract with Wolves and chose to take up Leeds' offer of a two-year deal instead.
He has been a stalwart of the Wolves defence since he arrived at Molineux from Sunderland for £1m in 2001.
The 31-year-old was capped once by the Republic of Ireland against the Czech Republic in 2000.