The newly elected MP won the seat from the Liberal Democrats' Sarah Olney with a majority of only 45 votes.
Mr Goldsmith lost his seat last year after resigning and calling a by-election in protest at the decision to expand Heathrow Airport .
There were no fewer than four recounts before a result was declared.
Mr Goldsmith won 28,588 votes, with Ms Olney receiving 28,543 votes on a turnout of 79%.
Mr Goldsmith admitted he had won by a "narrow margin" but thanked the voters of Richmond Park for giving him another chance to represent them.
''I hope my constituents know I will never let them down. " he added.
Ms Olney took the seat from Mr Goldsmith, who stood as an independent after his temporary departure from the Tories, last year.
The Lib Dem win was attributed to her opponent's pro-Brexit stance in the largely Remain-voting constituency.
Zac Goldsmith has retaken Richmond Park for the Conservative party in one of the most dramatic results of the election.