Federer, 32, the defending champion and world number four, was too powerful for the world number 69, as he claimed his second success of the season after Dubai in February.
It was Federer's 79th career title — and 14th on grass — and provided the Swiss with a timely boost ahead of his bid for a record eighth Wimbledon crown in a weeks' time.
There was a break of serve in each set before Federer took control in the tie-breaks to seal victory in 88 minutes.
Falla, 30, failed in his bid for a first ATP title, a year after also losing his first final in Bogota.
"I'm delighted with this victory and I hope I can continue to play well in the coming weeks," said Federer, who had slumped to a fourth round exit in the French Open.
Later on Sunday, Federer was to play the doubles with his friend Marco Chiudinelli, which could see him miss the start of Switzerland's World Cup opener against Ecuador in Brazil.
"I love football but I came here for tennis," said Federer, a crowd favourite since his first Halle title in 2003 after defending his only title of 2013.