Devindra Ferguson, 29, of Colindale, north-west London, shoved the man towards an oncoming train at Kentish Town station in December.
The victim Kamlesh Ramji sustained multiple injuries but has since recovered following hospital treatment.
At Blackfriars Crown Court, Ferguson was detained indefinitely to a secure mental health unit.
The Evening Standard reported that Mr Ramji suffered a fractured skull, brain injuries, a punctured lung, fractured ribs, a broken leg and a shattered pelvis.
The court heard the injuries the 40-year-old sustained were "traumatic and life-changing".
Mr Ramji told the court it was "hard to come to terms with or understand why a complete stranger would push me on to the tracks".
A man who pushed a commuter into the path of a London Underground train has pleaded guilty to attempted murder.