Storylines of the Kennedy family have included troubles within Karl and Susan's marriage over their 20 years in the show, which included two separation periods in the 2000s and a divorce, teenage angst storylines for their three children Malcolm (Benjamin McNair), Billy (Jesse Spencer) and Libby (Kym Valentine), Karl's interaction with other Erinsborough residents through his job as a doctor, Susan's professions as school principal and also briefly editor of the Erinsborough News, and the death of Libby's husband in a riding accident shortly after the birth of their son.
Benjamin McNair, Kym Valentine and Jesse Spencer played Karl and Susan's three teenage children, Malcolm, Libby and Billy, respectively.
Susan briefly remarries to Alex Kinski (Andrew Clarke) and their step-children become part of the extended Kennedy family, with both Billy and Malcolm having left the series several years earlier.
In this time she married twice and had a son, Ben Kirk (most recently Felix Mallard), whose father Drew (Dan Paris) died in a riding accident.
Karl's father Tom Kennedy (Bob Hornery) made guest appearances between 1996 and 2007, and was the first major character on the show to suffer from Alzheimer's disease.
[6] The Kennedys, Karl (Alan Fletcher), Susan (Jackie Woodburne), Malcolm (Benjamin McNair), Libby (Kym Valentine) and Billy (Jesse Spencer), move from Greendale[7] to Ramsay Street in late 1994.
They initially struggle to adapt, but soon become settled, with Karl going into partnership with Tamsin Caldo (Soula Alexander) at the local medical clinic and Susan becoming a teacher at Erinsborough High.
Billy befriends and gets into trouble with Toadie Rebecchi (Ryan Moloney), while Libby falls for Luke Handley (Bernard Curry), an older man and Malcolm starts a relationship with Danni Stark (Eliza Szonert).
Despite being reasonably stable in his marriage, Karl develops feelings for Kate Cornwall (Christie Sistrunk), a terminally-ill patient and confesses to Susan that they kissed before she died.
Karl feuds with Libby's boyfriend Darren Stark's (Todd MacDonald) mother Cheryl (Caroline Gillmer), but is devastated when, in trying to help her when she is knocked down by a lorry, he gives her drugs she is allergic to and she dies.
As a result, Karl stops medical practice briefly but continues when he saves Malcolm's life via an emergency tracheotomy, establishing his own surgery in the Lassiter's Complex.
Malcolm and Catherine leave together and later marry off-screen, although he returns in 2002 as a ruthless businessman to open an English-based coffee shop in Erinsborough.
Susan becomes suspicious that Karl has feelings for their neighbour, Izzy Hoyland (Natalie Bassingthwaighte), and Malcolm shares her suspicions when he briefly returns.
While Karl and Izzy have a brief romance, Susan starts a relationship with Alex Kinski (Andrew Clarke), and he moves in with her, along with his two children Rachel (Caitlin Stasey) and Zeke (Matthew Werkmeister).
Rachel and Zeke both eventually move out, with various lodgers including Summer Hoyland (Jordy Lucas) and Natasha Williams (Valentina Novakovic) living with the Kennedys at times.
Susan's boss Paul Robinson (Stefan Dennis) sells the Erinsborough News and Sarah Beaumont returns to oversee the merger between it and the West Waratah Star.
The Kennedy family, and Karl and Susan in particular, are considered an icon of Neighbours not just because of their long tenure on the show but also due to their memorable mix of comedic and dramatic storylines.
[10] In 2010, to celebrate Neighbours' 25th anniversary Sky, a British satellite broadcasting company profiled 25 characters of which they believed were the most memorable in the series history.
They said that "Susan Kennedy from Neighbours manages to be the comforting mother figure as well as coming down hard when necessary", and praised her for showing "the highs and lows of the job".
[12] In June 2014, Kerry Barrett from All About Soap was pleased to see Libby return, saying "We were just as thrilled as the Kennedys were to see lovely Lib back in Erinsborough.
"[13] The returns of other characters including Holly Hoyland and Malcolm Kennedy were also praised as a worthy celebration of Susan and Karl's 20 years on Neighbours.
[14] In February 2015, British actor and Academy Award winner Eddie Redmayne revealed to a journalist from Elle UK magazine that he uses the work of Karl and Susan as acting inspiration.