Hill-Wood, who has been the Gunners chairman since 1982, has stepped down as he continues his recovery from a heart attack last year.
As a result, it signals the end of an era for the family, with Hill-Wood’s grandfather and father both previous chairmen at the north London side.
Hill-Wood, 77, said: “This has been a difficult decision as Arsenal Football Club has been a huge part of my life.
“Although I am feeling better I feel this is the right time for me to stand down. I would like to thank our majority owner, Stan Kroenke, for the respectful and dignified way he has handled this and I know Sir Chips is the right person to take the Club forward.”
Keswick, 73, who is the former chairman of Hambros Bank and a director of the Bank of England, has been on the Arsenal board since 2005 and in his role of chairman, will now work on the club’s football and business ambitions, alongside chief executive Ivan Gazidis.
The new chairman said: “Firstly, I am sad to see Peter standing down due to his health and we all hope he continues well in his recovery.
“The Hill-Wood family has made an extraordinary contribution to Arsenal over many decades. They have been central to the club’s many achievements during this time.
“I am greatly honoured to have been appointed chairman of Arsenal Football Club. This is one of the great clubs in the game, recognised and loved by millions. I am looking forward to leading the Club to future success.”
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news