Thousands of athletes of all abilities took part in the new day-long event around St James' Park.
Paralympic athletes David Weir and Richard Whitehead also took part in the race which finished outside Buckingham Palace.
The Bupa Westminster Mile featured more than 30 races.
Farah said: "I am very happy to be part of this new event taking place on the most famous mile in the world, following the 2012 Olympics and Paralympics in London.
"Such an event inclusive of all age groups and abilities, is a great legacy from the (Olympic) games and an inspiration to all."
Lisa Dobriskey - who in 2009 broke the four minute barrier to move second behind Kelly Holmes on the British all time ranking list for a 1500m race - also took part.
The event was organised by the London Marathon in partnership with Westminster City Council.
London Marathon race director Hugh Brasher said: "Britain has an amazing heritage in the mile, with Sir Roger Bannister being the first person to run under four minutes and more latterly the 1980s world record holders Sebastian Coe, Steve Ovett and Steve Cram.
"We believe that this exciting new event can carry on the great work that London 2012 Olympic and Paralympic Games did to inspire a generation."
Double Olympic gold medal winner Mo Farah fired the starting pistol on a series of one-mile races in Westminster.