The third-seeded Raonic fired 24 aces in the match that took one hour and 49 minutes to complete. He converted three of six break points while saving four of five break points against.
Raonic will face France's Richard Gasquet in the second round.
The hard server from Thornhill, Ont., is returning after having an operation France to help a condition that usually involves the thickening of the tissue around a nerve leading to a toe. The surgery caused him to miss the French Open.
The Aegon Championships is a warmup event fro Wimbledon, where Raonic was a semifinalist last year.
Gasquet earned his 400th ATP tour victory Monday by beating Italian qualifier Simone Bolelli 6-1, 6-2 in just 56 minutes to reach the second round.
Gasquet is the third Frenchman to reach that milestone in the Open era, after Yannick Noah (476 wins) and Fabrice Santoro (470).
The match between defending champion Grigor Dimitrov and 2010 tournament winner Sam Querrey was suspended overnight at one set apiece.
Four-time champion Lleyton Hewitt had a match point against South African Kevin Anderson but lost 6-7 (5), 7-5, 6-2. Anderson had 22 aces.
Hewitt, the Australian veteran who made his Queen's Club debut in 1998 at the age of 17, was playing the event for a 16th and final time before retiring at the Australian Open next January.
Hewitt was unable to convert any of the five break points he held in the first set before winning the tiebreaker. He then held a match point when serving for the match at 5-4 in the second but Anderson saved it and went on to dominate the final set.
In two all-Spanish matches, Fernando Verdasco saved three match points before edging Roberto Bautista Agut 3-6, 7-5, 7-6 (4), and Guillermo Garcia-Lopez defeated Pablo Andujar 7-6 (3), 6-2.
The tournament is a major warm-up for Wimbledon and has been upgraded to an ATP 500 event with an additional $1 million in prize money.
Andy Murray, French Open champion Stan Wawrinka and Rafael Nadal are also in the 32-player field. Nadals is playing at Queen's Club for the first time since 2011.