Watched by his wife, Mirka, and his twin girls, Federer moved gently through the gears against the shaggy-haired Slovakian under grey skies on the Philippe Chatrier show court.
The former champion, who has returned to something close to his best form after a disappointing 2013, admitted a trace of fear before the start of the year's second grand slam.
"I wasn't nervous actually going into the match," said Federer, 32. "It's more just like those hints of fear, maybe yesterday, maybe this morning at one point, just for like five seconds 'Oh, I really hope I don't have to pack my bags today', that kind of feeling."
But he had little to fear from Lacko and by mid-afternoon he was once again in a position to help Mirka look after their newly born twin boys. "Everything is great," Federer said.
Sixth seed Tomas Berdych beat Peter Polansky of Canada in straight sets while Jo-Wilfried Tsonga, the 13th seed, overcame fellow Frenchman Edouard Roger-Vasselin 7-6(4) 7-5 6-2.
Raonic pushed Novak Djokovic in the Rome semi-finals before losing in three sets to the eventual champion and he eased through the first set against Kyrgios.
The eighth seed was broken midway through the second but recovered immediately, leaving his 19-year-old opponent to hurl his racket to the court, shaking his head.
The Australian got increasingly frustrated through the second-set tiebreak, berating himself repeatedly, before Raonic took it 7-1.
A finely executed forehand slice from the back of the court forced Kyrgios to hit long, giving Raonic a 2-0 lead in the third set. But it was soon Raonic's turn to berate himself as a double fault gifted back the break of serve.
Another break in the sixth game put Raonic on course for a three-set victory and he served out to win on his third match point.
"I felt very good," said Raonic.
"I was able to do the things I wanted to do. In the first round you go in not knowing exactly how things are going to play out, and I was able to, when it mattered, put forward the right attitude and the right level of tennis."
Results from the French Open Men's Singles Round 1 matches
Jeremy Chardy (France) beat Daniel Gimeno-Traver (Spain) 7-5 6-2 6-2
20-Alexandr Dolgopolov (Ukraine) beat Albert Ramos (Spain) 7-6(4) 6-4 6-1
13-Jo-Wilfried Tsonga (France) beat Edouard Roger-Vasselin (France) 7-6(4) 7-5 6-2
Sam Querrey (U.S.) beat Filippo Volandri (Italy) 7-6(3) 6-4 6-3
31-Dmitry Tursunov (Russia) beat Potito Starace (Italy) 6-1 7-5 6-2
10-John Isner (U.S.) beat Pierre-Hugues Herbert (France) 7-6(5) 7-6(4) 7-5
22-Jerzy Janowicz (Poland) beat Victor Estrella (Dominican Republic) 6-1 6-4 6-7(6) 6-4
6-Tomas Berdych (Czech Republic) beat Peter Polansky (Canada) 6-3 6-4 6-4
Jarkko Nieminen (Finland) beat Michal Przysiezny (Poland) 6-7(7) 6-4 6-7(3) 6-3 6-4
Radek Stepanek (Czech Republic) beat Facundo Argueello (Argentina) 6-7(8) 3-6 6-4 6-3 6-2
Aleksandr Nedovyesov (Kazakhstan) beat Somdev Devvarman (India) 5-7 6-3 7-6(4) 6-3
15-Mikhail Youzhny (Russia) beat Pablo Carreno (Spain) 3-6 1-6 6-3 6-4 6-0
4-Roger Federer (Switzerland) beat Lukas Lacko (Slovakia) 6-2 6-4 6-2
8-Milos Raonic (Canada) beat Nick Kyrgios (Australia) 6-3 7-6(1) 6-3
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