Alexander, who had previously been the International Kart Federation’s champion (100cc Yamaha class), was one of the top five finalists in the 2005 Red Bull Driver Search, a competition which had attracted over 2000 entries.
Aged just 14, in 2006 he headed, armed with a scholarship, to the famous Skip Barber Racing School where he contested its National Championship. Making history by becoming the youngest ever race winner, Alexander went on to finish the season third overall.
In 2007 he contested the Formula BMW USA series with Team Apex Racing, finishing third overall courtesy of three wins and five podiums. He remained in Formula BMW for 2008 but switched to EuroInternational, a move which saw him win the title thereby becoming the first American Formula BMW Champion.
He ended the year as Formula BMW world champion having won the final at the Autodromo Hermanos Rodriguez circuit in Mexico City. As part of his prize, alexander was awarded an F1 test with the BMW Sauber F1 team, along with European champion Esteban Gutierrez.
2009 saw Alexander follow the example of many racers before him, the American youngster packing his bags and heading to Europe. After much thought he opted to contest International Formula Masters with Hitech Racing however, after just two rounds he opted to join ISR Racing. He went on to win three races - Brno, Spa and Imola - ironically, all of them featuring reversed grids. At season end he was fourth overall, the highest-placed rookie driver.
Over the winter of 2009/2010, Alexander tried his hand at the GP2 Asia series. Having contested the opening round (Abu Dhabi) with Ocean Racing Technology, he subsequently switched to Team Meritus. Ironically, his best result of the championship came in his maiden race in which he finished fourth, eventually ending the season ninth overall.
Another year, another discipline, 2010 seeing Alexander contest the inaugural GP3 Series with ART Grand Prix. Wins in the opening round (Barcelona) and again at the Hungaroring, together with podium results in Turkey, Britain and Belgium, were enough to secure fourth in the title fight, albeit losing out to teammate Esteban Gutierrez who won the title.
For 2011 he headed to Formula Renault 3.5 Series with Fortec Motorsport, finishing third in the championship with wins at Aragon and Le Castellet. He remained in the series for 2012 but switched to newcomers Arden Caterham Motorsport. It was a disappointing season, the American making only one visit to the podium (Monaco) and finishing the year 11th overall.
2012 wasn't all bad however, for in March he was revealed as test driver for Caterham, along with Dutch youngster Giedo Van der Garde. Having gained his superlicence courtesy of his test with the BMW Sauber team, Alexander had been linked with the stillborn USF1 project but it was not to be. In Spain he replaced Heikki Kovalainen in FP1, thereby becoming the first American to drive an F1 car over a race weekend since Scott Speed at the 2007 European Grand Prix.
Alexander was retained as test driver with Caterham for 2013 whilst also contesting the GP2 Series with the Anglo-Malaysian outfit. He participated in the Friday morning sessions at Montreal and Austin and also at the Young Driver Test at Silverstone.
In GP2 he finished ninth overall, a fairly disappointing season concluding with a surprise win in the Feature Race in Abu Dhabi. Other than that, there were only three other visits to the podium.
The youngster also found time to contest the Le Mans 24 Hours with Greaves Motorsport, driving a Zytek Z11SN he and co-drivers Tom Kimber-Smith and Eric Lux finished 23rd overall and ninth in class.
On 21 January 2014, Caterham announced that Alexander had been retained as its test and reserve driver and would also continue in GP2 with Caterham Racing.
While there was no pre-season or even in-season testing with Caterham in 2014, he did get to take part in FP1 in Canada, the American was also scheduled to take part in a number of other such sessions later in the year.
However, in the wake of Tony Fernandes 'departure' from the team, Alexander announced he was parting company with Caterham, popping up just five days later at Marussia.
Less than a month later, on the Thursday of the Belgian Grand Prix, it was announced that Alexander would replace Chilton due to "contractual issues". However, next morning, during FP1 the move was reversed and while nobody was willing to say too much it is understood that there was a difference of opinion over money with the Briton's backers and the team had to make a point.
Though it was rumoured the American would take part in FP1 at Austin, the tragic events of Suzuka and beyond meant it was not to be.
As Jules Bianchi's fight for life continued in a Japanese hospital it was expected that Alexander would replace him at Sochi however, out of a mark of respect for the Frenchman the team opted to run just one car for Max Chilton.
Events at Caterham meant that Alexander's GP2 season came to an early end and though he contested the Hockenheim round with Campos he subsequently withdrew from the series.
In the wake of the collapse of Marussia, Alexander's plans for 2015 were in limbo, and while he was linked with Indy Car, the youngster was clearly aware that Haas F1 is due to enter the sport in 2016.
Consequently he remained in GP2, joining Racing Engineering with whom he enjoyed a podium result in the first race of the season. Further podium results followed, including runner-up in the feature races at Monaco and Silverstone.
A win in the sprint race at Spa was followed by another in the feature race at Monza, thereby promoting Alexander to second in the standings.
Days later however, the youngster received a slap in the face when Haas team principal Guenther Steiner ruled out a 2016 F1 drive.
Asked if the team might employ an American driver, Steiner said: "There is nobody out there at the moment. Yes, there are drivers in GP2 and F3, but having a rookie in a new team... that is difficult for both sides."
However, on the eve of the Singapore weekend, Manor announced that Alexander would replace Roberto Merhi in five of the remaining races.
Whilst most would (quite rightly) baulk at the idea of making their F1 debut on a street track, especially Singapore, Alexander relished the opportunity and got stuck in. Though he qualified last, the American was to finish the race ahead of his teammate. Indeed, of those five races, only once did Stevens finish ahead of the American.
In qualifying, whilst initially trailing to Stevens, in his final three appearances the American out-qualified his teammate.
Despite the obvious pressure, not to mention the weather, Alexander rose to the occasion in Austin, bringing the Manor home 12th – thereby equalling the team's best finish of the year - at one point even looking as though a points finish might be possible.
Of course, there is a real need to have an American on the grid however, we're sure Alexander would rather be out there on merit as opposed to ticking a box. Fact is, based on those five outings, if not finishing runner-up in GP2, Alexander deserves another shot, and Haas' stance seems somewhat short-sighted.
In late February, as the opening F1 test got underway in Spain, it was announced that Alexander would make his IndyCar Series debut with Andretti Autosport.
On March 9, days after his rookie test at Sebring International Raceway, it was announced that Alexander was returning to "the Manor Racing fold" as official reserve driver, though racing in IndyCar, he would also perform a Formula 1 role simultaneously.
"Rossi will attend 11 Grands Prix with Manor Racing," said the team, "where he will work with the engineers and drivers to help develop the MRT05, contribute to team and partner marketing activities and be available to deputise should he be required to compete at short notice. His first F1 event will be the Russian Grand Prix in May."
F1 still very much at the forefront of his ambitions, one has to assume that the deal is better than nothing, though it's hard to see exactly how it will work.