Nik Wallenda braved wind and heavy spray to complete the walk on a 2- inch wire.
The televised stunt was watched by thousands from Goat Island in US.
It is the first such feat over Niagara Falls in over a century.
Mr Wallenda is the seventh generation of the famed Flying Wallendas, who had performed for over
Mr Wallenda wore a safety harness attaching him to the wire, a precaution insisted on by the US broadcaster ABC.
The 33-year-old had estimated the total cost of the walk would be around $1.3m (£830,000), including creating and installing the steel wire, as well as permits and security on both sides of the border.