After a successful career in karting, Kevin, son of 1994 British F3 Champion and Stewart F1 driver Jan Magnussen, made the switch to single-seaters in 2008, winning the Danish Formula Ford championship with an impressive record of 11 wins, 12 podiums, 6 pole positions and 10 fastest laps.
The following year, he graduated to Formula Renault 2.0, finishing runner-up in the Northern European Cup and seventh in the Eurocup. In the NEC, he scored one win, 12 podiums and two pole positions - achievements that earned him the 'Rookie of the Year' accolade.
In 2010, he moved into German F3, impressing immediately by taking victory in the opening round of the season. It was the first of three victories on his way to securing third in the championship and once again being named 'Rookie of the Year'.
Kevin also joined the McLaren Young Driver programme in 2010, dovetailing his racing activities with training and development work with the legendary F1 team with which his father made his F1 debut - a one-off outing with the Woking team in the 1995 Pacific GP at the Aida Circuit where he replaced Mika Hakkinen who was recovering from appendicitis.
In 2011, he moved into British F3, building upon the successes of the previous season. He finished second in the championship after securing seven race wins, six pole positions and eight fastest laps.
As a result, his F3 team, Carlin Motorsport, signed him up for 2012's World Series by Renault 3.5 series. As a rookie, he won once and took three further podium spots, but the year helped him sharpen his teeth before a full assault on the WSR title in 2013.
With a year's experience under his belt, Kevin underlined both his speed and maturity, slowly tightening his grip on the title, before underlining his supremacy by dominating the series' final two rounds.
It was this blend of assurance, maturity and potential, as well as a pair of stunningly impressive testing outings at Abu Dhabi and Silverstone, that helped him land the drive with McLaren for 2014.
As the first Dane to start an F1 race for a decade - Nicolas Kiesa raced for Minardi at the tail-end of 2003 - a nation's gaze was directed towards him when he lined up on the grid for the season opener.
In pre-season testing the MP4-29 was strong, not least due to the fact that Mercedes had clearly mastered the new formula. Kevin topped the overall times at Jerez and was third overall in the opening test in Bahrain. By the end of the final test he had slipped to sixth, but no cause for alarm.
The season got off to the worst possible start when Kevin and Button finished second and third in Melbourne, courtesy of Ricciardo being disqualified for fuel irregularities.
We say 'worst possible start' because basically this is as good as it got. Though there were some good performances, they were few and far between and never totally convincing. Furthermore, whilst clearly running the best power unit on the grid the spectre of Honda and the 'ghost of season to come', continually hovered over the Woking outfit.
In total the Dane score points in twelve of the season's nineteen rounds, but by the end of the year had totalled around a third of the point scored by his iteammate. Worse, though considered "lightning quick" Kevin was trounced 10-9 in qualifying.
For the most part, Button had the measure of Kevin, the Briton's consistency and experience winning out, particularly in the second half of the season, whilst, other than Russia, the Dane's challenge all but fizzled out.
On December 11, after weeks of speculation, the team confirmed that Fernando Alonso was returning to Woking, the team finally also putting Button (and his fans) out of their misery by confirming the Briton for a sixth season.
Kevin is retained as test and reserve driver, whilst vandoorne pphotlinkhighlight}Stoffel Vandoorne is also kept on the books, a fact that will not be lost on the Dane.
It is clear that, like his father, Kevin has talent, however, again like his father, could it be that F1 is just that little too high a step for the youngster? In Melbourne he appeared to confirm what many suspected, that a talented new kid had arrived on the grid, but from then on it all went to nothing.
Whether Kevin gets a second crack of the whip is up to him, and whether the reserve seat will give him the opportunity is doubtful.
Another one season wonder? Possibly.