Federer beat Cilic in straight sets on Centre Court 6-3, 6-1, 6-4 to win a record eighth Men's Singles title at Wimbledon.
The Swiss has now won the two majors he has played this year after having an extended break at the end of 2016 and missing the French Open.
It is the 35-year-old's first win at the All England club since 2012 and has increased his Grand Slam tally to 19, which itself is a record.
Former semi-finalist Henman was full of praise for Federer, especially after how long he had off just a few months ago.
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Who writes these boys' scripts? It's just unbelievable
Tim Henman on Wimbledon champion Roger Federer
"Who writes these boys' scripts?" Henman said on the BBC.
"It's just unbelievable. Six months ago if you said to the tennis fraternity, Federer is going to come back and only play two Slams this year and win them both, you would have got pretty long odds today."
Cilic struggled through the match due to a problem with his foot.
Roger Federer beat Marin Cilic to win his eighth Wimbledon title
The Croat was in tears during a medical timeout and was clearly in severe discomfort in what was his first Wimbledon final.
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