The 24-year-old made his Olympic debut at the Beijing Games in 2008, a year after his World Championship bow in Melbourne, and reached the final of the 200m freestyle.
Renwick didn't even compete over the distance at the worlds in Australia 12 months beforehand but was to touch home in eighth as the only Brit in an ultra-competitive final.
In the build up to the next Olympics in London, Renwick made two more appearances on the world stage but didn't reach a single individual final in Rome in 2009 and Shanghai in 2011.
He was 14th in his only individual event, the 400m freestyle, in Italy where the now banned polyurethane suits took centre stage before placing 18th in the same discipline in China.
Renwick underlined his promise at the Delhi Commonwealth Games in between in 2010 though, taking 200m freestyle gold before competing in the event for the first time at a worlds in 2011.
He placed 12th overall in Shanghai and then secured swims at the London 2012 Olympics by claiming his first ever British 200m title as part of a golden double with the 400m crown secured too.
Renwick opened his account in London by ranking 11th after the heats of the 400m before again being the only Brit to advance to the final of the 200m at the Olympic Aquatics Centre.
He improved on his placing from Beijing to finish sixth but, along with the rest of the British swimming team, bore the brunt of a medal haul of just three when five to seven were wanted.
With that have come a raft of changes and retirements but Renwick has stuck around and is determined to make the step up at this summer's World Championships in Barcelona.
"The World Championships this summer is the first chance for British Swimming to set the record straight after London," said Renwick.
"Although the results were disappointing we did get the record number of finalists and that is great for the next generation of athletes coming through.
"We have got great depth now so this summer and the Commonwealth Games in Glasgow next year will be a great chance for us to bounce back.
"Hopefully I will get on the team for the World Championships but I won't settle for that, I want to be gunning for a medal as well.
"I was happy to make a final, a top six, and improve my personal best at London 2012 but there is no doubt that a lot of British swimmers came away disappointed with what they achieved.
"They will have something to prove this summer and that is only going to make our team stronger moving forward so we should come back with a few medals to celebrate."
Of the changes post-London 2012 Michael Scott has left as British Swimming performance director as has Dennis Pursley as head coach, although that was announced before the Games.
Chris Spice has come in for Scott and Bill Furniss, the man who led Rebecca Adlington to double gold in Beijing and double bronze in London, has come in for Pursley.
Adlington has retired along with the likes of former world champion Gemma Spofforth while British Swimming's funding was slashed by almost £4million at the end of last year.
A review into the London 2012 performance, not only led to Scott's departure but also saw the British Championships, which act as the trials for the major event of the year, moved.
Instead of March they are now in June and the change, as hoped, could be a desired one with Renwick admitting he is at level in training that he has never reached before.
"On a personal level I'm really happy with my form at the moment, I'm hitting the fastest times that I have ever had in training," added Renwick.
"There has been a lot of focus on building up my strength in training and that is paying dividends.
"I've never been swimming faster midway through a season before and that can only be a good indication coming up to the qualifying meets for this summer's World Championships."