Following his retirement as a player, Bartlett developed a successful career as a sports commentator and broadcaster on both television and radio. He was a member of the AFL's rules committee for many years until replaced on 4 March 2014. as well as the selection panel for the All-Australian Team and AFL Rising Star awards. In 1988 he was appointed coach of Richmond, but his sacking after four unsuccessful seasons led to Bartlett not returning to the club for the following 16 years.
Bartlett was a rover and goalkicker who was known as 'Hungry' due to his unwillingness to handball. He is known for great evasiveness and stamina, he could win a game off his own boot. A winner of five premierships with Richmond, he also won the Norm Smith Medal in 1980 after kicking seven goals in the Grand Final. With 403 games, only Michael Tuck of Hawthorn has played more VFL/AFL games. Bartlett was renowned for his skill and concentration on the game and was instrumental in many Tiger wins.
Bartlett grew up barracking for the Footscray Football Club, and watched their only premiership in 1954. As a teenager, he walked from his home in Lennox St, Richmond to the Punt Road Oval, where he was greeted by Richmond's Fourth coach Bill Boromeo. It was this chance meeting that set in the motion for Bartlett to eventually play at Richmond. He began his career with the under 17's side where he won the goalkicking and the best and fairest in 1962. In 1963, he won the Best and Fairest in the under 19's and Richmond made the under 19's final series. Bartlett however was injured seconds into the first final against Geelong, which resulted him being taken to the Prince Henry Hospital where it was revealed that a cyst was embedded in his hip. It was while waiting for the ambulance to collect him in the MCG change rooms, that he first met Jack Dyer. Dyer had appeared at the match on advice of Richmond under 19's coach Ray Jordon – and visited Bartlett in the rooms to tell him he will be okay. The following year for Bartlett (1964) involved rehabilitation, as he still experienced pain around his hip area.
Bartlett was the Tigers' coach from 1988 to 1991. Controversy surrounding his dismissal as coach left him estranged from the football club for many years. However, on 30 March 2007 he attended his first official club function since 1991.
Bartlett joined Channel 7 in Melbourne immediately after his playing retirement, appearing regularly on World of Sport and hosting the Junior Supporters Club. In 1984, Bartlett was crowned King of Moomba. He also wrote for the Sun News Pictorial. His media commitments were put on hold during his four-year stint as Richmond coach. He has great all-round interest in most sports, and is one of the few ex-Australian football players who has carved out a career commentating on all manner of sports. Currently, he hosts Hungry for Sport, a radio show playing on his nickname of "Hungry", on Melbourne's dedicated sports radio station, SEN and commentates Saturday and Sunday matches for them. He previously had commentated on cable-TV for Fox Footy and was the host of the popular nostalgia show Grumpy Old Men on Fox Footy until the channel's closure at the end of the 2006 season.
On 13 September 2008, he appeared in a Toyota Memorable Moments advertisement. The advertisement includes Bartlett recreating his seven goals from the 1980 VFL Grand Final, as well as his famous 'comb-over' hair style, which comedian Dave Lawson recreates by shaving his own hair on camera. Geelong's Matthew Scarlett impersonated the haircut, at his 'Mad Monday' celebrations after the 2008 Grand Final 
Bartlett's refusal to return to any Richmond Football Club function, or an official club arrangement lasted from the end of 1991– until 2007. In 2007, he attended a Tommy Hafey Club Function – in support of his lifelong friend Tom Hafey and on 22 November 2007, walked into the Punt Road ground (Richmond's Home Ground) to launch the centenary publication 'Richmond F.C: A Century of League Football', which was written by his son Rhett. It was the first time KB had stepped foot into Punt Road, since his sacking at the end of 1991.
Bartlett was made a Member of the Order of Australia in 1981, and was inducted into the Australian Football Hall of Fame and Richmond Hall of Fame in 1996 and 2002, respectively; he was promoted to "legend" status in the Australian Football Hall of Fame in 2000 and to "immortal" status in the Richmond Hall of Fame in 2004. He was also named as part of Richmond's team of the century. He was inducted into the Sport Australia Hall of Fame in 2006.