Lyon became only the third Australian to reach the milestone when Dinesh Chandimal hit him to a diving Beau Webster on Saturday in the second Test against Sri Lanka.
The veteran off-spinner (3-80) took two more wickets into the sheds on the third day in Galle as Australia (414) closed in on a 2-0 series win over the hosts (257, 8-211).
Lyon could conceivably pass Glenn McGrath (563) by the end of the calendar year to hold the second-most wickets of any Australian, but Shane Warne (708) is some way off.
"I hate talking about it but it is something I'm extremely proud about," Lyon said of his milestone.
"It's pretty cool when you look at it. When I debuted 14 years ago or whatever it was, I didn't think I'd take 550 wickets. To pick up that one here is very special."
On the same turf in Galle in August of 2011, Lyon made his Test debut as a former groundskeeper with a penchant for finger spin.
Lyon has since added 135 more Test caps, and lost a fair bit of hair, but his memories of that match in Galle remain clear.
"That was a long time ago," he said.
"I was pretty raw, I didn't really know what I was doing.
"I just remember Ricky Ponting and Mike Hussey just came up and said, 'Have a bit of fun, trust your skill and bowl your best ball'."
The advice clearly worked.
The 23-year-old Lyon became the first Australian since Keith Miller in 1946 to take a wicket with his first delivery in Test cricket as Kumar Sangakarra edged him to the slips.
Sangakarra was the ICC's number-one ranked Test batter at the time and retired with the most runs for any Sri Lankan player in history.
Lyon has become one of the greats himself. No Australian off-spinner has taken more wickets and only four of his countrymen have played more Tests.
As much as things have changed, Ponting and Hussey's advice has been a constant on Lyon's rise to Test greatness and 550 wickets.
"They're three things that have stuck with me throughout my whole career," Lyon said.
"I'll keep doing that 'til the day I retire, but that's a long way away. I'll keep enjoying it, keep trusting it and keep bowling my best ball, and see how we go."
Australia have not won a Test series in Sri Lanka since that 2011 visit on which Lyon debuted, but are on the cusp of securing a 2-0 sweep on day four.
The spinners had struggled for a breakthrough late on day three before fellow veteran Angelo Mathews (76) clipped Lyon to Webster in the deep.
Sri Lanka are only 54 runs ahead at 8-211, and Lyon will do whatever it takes to get those final two scalps.
"I'm happy to bowl all day. I'll rest when I get home," Lyon said.
20°C