Former Newport County academy coach James Rowberry is also being promoted to an assistant role.
The Wales national squad's head of performance Ryland Morgans joins the Bluebirds as performance director.
Former first-team coach Scott Young becomes academy defence coach and club ambassador.
Morgans has previously worked for Liverpool - with ex-manager Brendan Rodgers - and Fulham and has been part of the Wales coaching set-up with Trollope.
Lawrence returns to the Bluebirds for a second stint, having originally joined as a consultant in 2002. He worked with Trollope previously at Bristol Rovers.
The 68-year old then succeeded Alan Cork as Cardiff boss and led them to promotion in his first season, winning the Football League second division play-off in 2003 against QPR.
Goalkeeping coach Martyn Margetson has also agreed a new contract to stay at the Cardiff City Stadium.
"We are delighted to bring people with the experience Dr Ryland and Lennie have to the club and hope that they can play an important role in helping us achieve our ambition of promotion back to the Premier League," chief executive Ken Choo said.
"We have put together a strong backroom coaching team this summer which we believe will help maximise the potential within our playing staff."
Head coach Paul Trollope added: "I am delighted to finalise my backroom staff ahead of the forthcoming season.
"We've worked very hard over the past month to secure their services and I feel it's a highly experienced, driven and ambitious staff."
Cardiff City have confirmed that Lennie Lawrence is returning to the club as assistant coach to new boss Paul Trollope.