He's been called everything from a superstar to a spoiled brat.
He won an IndyCar Series race as a 19-year-old rookie under suspicious circumstances, but honest victories that could or should have come his way since that breakthrough have slipped through his hands.
He's learned the hard way that being from one of racing's royal families can work both for and against a driver.
Now a grizzled veteran at the age of 21, Marco Andretti returns to Infineon Raceway this weekend exactly two years removed from his lone IndyCar victory, still carrying the weight of unrealistic expectations that come with having one of racing's most famous surnames.
It's a good venue for Andretti to be headed to, because he came close to winning at the undulating road course in Sonoma, Calif., again last year -- once again shrouded in controversy, albeit not as blatantly as back in 2006.
Marco qualified on the outside of the front row for his rookie run at Infineon and took the lead on the 51st of 80 laps. Andretti had stopped six laps earlier, and it soon became obvious he was trying to run to the finish without making another pit stop.
He had his Andretti Green Racing teammates Dario Franchitti and Tony Kanaan directly behind him running interference on Scott Dixon and the rest of the field, but to make it to the end, Marco would clearly need another full-course caution.
On the 72nd lap, it miraculously came. Running in seventh place, AGR's fourth driver, road-course specialist Bryan Herta, made a surprisingly elementary mistake and spun and stalled at Turn 7. Out came the pace car, and into Victory Lane drove Andretti, while Kanaan (who ran the same pit-stop strategy as Andretti) was forced to pit for fuel on the penultimate lap.
To this day, Herta denies he spun on purpose to bring out the yellow. But it certainly looked like teamwork of the most disingenuous kind.
Andretti's No. 26 team also played the fuel game at Infineon in 2007 to move their driver to the front. Teammate and championship leader Franchitti made a late splash-and-go and appeared on the brink of winning the race and sealing the title, until Andretti raced him aggressively for the win and spun the Scotsman off the track -- and ultimately out of AGR.
What Marco needs right now more than anything is a clean, decisive victory, one not tainted by talk of fuel strategy or team orders. And Infineon is a logical place for it to happen.
"Oh yeah, for sure," he said. "Last year we almost won from starting eighth; I was in the lead when we got taken out. So I'm looking forward to going back there this year.
"The big question of 'When are you going to get your first win?' isn't there for me anymore," Andretti added. "Now the big question is: 'When are you going to start winning?' That's the question I'm asking myself, and I definitely think with as much bad luck as we've had, when it turns around we can set the world on fire. If it swings our way, we'll be right there."
Statistics indicate that the kid isn't talking smack. Marco ranks fourth in laps led this year (with 330), yet lies a disappointing seventh in the championship standings. That's because his season has been hit or miss, with six top-5 finishes offset by seven DNFs.
Like Andretti, Helio Castroneves hasn't won a race in 2008, yet consistency has landed the Brazilian second in the points race. He's failed to complete only three laps (out of 2493) this year, whereas Andretti ranks 14th in that statistical category.
He was crushed not to win two weeks ago at Kentucky Speedway after driving a cool and heady race. A third-place finish was scant reward, but still, that was better than what befell Andretti at tracks like Richmond, where his No. 26 Dallara/Honda was a rocket until it suffered a suspension failure and subsequent crash.
"It's definitely a little snake-bitten, because there was a lot that was out of my control," Andretti said. "The bummer is that all of a sudden we look and it's another bad season. But we're all human, and we are a team. When the suspension breaks, that's the risk we take before we get in the car. It's nothing that I'm going to hold grudges about.
"You know what?" he continued. "Just as much as things go wrong, they can easily turn around. I've done nothing different as far as my driving from '06, when I was Rookie of the Year and when I was on top of the world at Indy. The one thing that really keeps my head in it is if you look back at a lot of the races this year, we led most of them. We just need results, and that definitely is a key."
AGR co-owner Michael Andretti believes his son has made tremendous strides since his rookie campaign. Michael took some heat for promoting Marco into his IndyCar team when the 19-year-old had competed in only a handful of oval races, but Marco's performances have often proved his father was justified in taking the risk.
In many ways, Marco's career has paralleled Michael's, although Michael did not win a race as a rookie. In fact, Michael's second and third IndyCar seasons (1984 and '85) were relatively disappointing after the form he showed in a handful of starts in late 1983. But once he broke through (at Long Beach in the 1986 season opener), Michael remained a regular race winner and championship threat for the rest of his long and distinguished career.
"Honestly, he's had a really tough year," Michael Andretti observed. "I think if you look he's had probably two self-inflicted mistakes -- Motegi, where he broke the halfshaft in the pits, and Milwaukee. I think he got blamed for some others. So he's had tough luck, especially at places where he was going to be really good in the race.
"Where I have been really most proud I would say out of all the races, probably 80 percent of the time the setups have drifted towards what he developed," Michael added. "That's what's been really impressive. Last year at this time he was starting to get it down, but from where he was at the beginning of last year to where is now is like he's two different people."
There is definitely a faction of the IndyCar paddock that snickers at the fact that Marco was given a seat in the family team -- one of IndyCar's top teams -- without really earning his stripes. Michael drove five seasons for Kraco Racing before he was invited to drive for Newman/Haas Racing, a team built around his own father, Mario Andretti.
Graham Rahal competed in the Star Mazda development series at the same time as Marco Andretti and achieved much more success. Rahal's career path took him into Formula Atlantic while Andretti was given an opportunity to compete in the Indy Pro Series (now Firestone Indy Lights) in a car entered by AGR.
Rahal was impressive enough in Atlantic to get hired on merit by Newman/Haas to race in the Champ Car World Series in 2007. The son of three-time IndyCar champion Bobby Rahal says he would not want to drive for his father's team so early in his career, even if the opportunity had been handed to him.
"I think [driving for AGR] is hurting him," Rahal said of his rival. "For his reputation it would have been better to be with someone else to kind of prove that he did it on his own.
"But you know what? That family has always been that way. If you look at Michael and Mario, they were always on the same team. Michael wants Marco to drive for him. There's just different mentalities about it. There is no right way and no wrong way."
Rahal is not the only IndyCar driver who believes that Marco's growth as a driver could be greater if he stepped out from the shadow of his father.
"I'd like to see him go to another team," said championship leader Dixon. "I think it would be good for him."
"I'm in a similar situation," admitted Vision Racing's Ed Carpenter, whose team owner is his stepfather, Indy Racing League founder and Indianapolis Motor Speedway CEO Tony George. "I think a lot of days there is more pressure because you always want to please your parents more than anybody else. But there is less pressure because I think you are in a little more stable situation, running for a family.
"It can go either way. Personally, I love racing for my family. I don't know exactly his relationship with Michael so it can be good or bad. Mine's good, so his probably is too."
After his initial five-year stint with Newman/Haas, Michael Andretti drove in Formula One for a year and spent a season with Target/Ganassi Racing before he returned to Newman/Haas, the team he was most closely associated with, for another six-year tenure. He rounded out his IndyCar career with Team Green, ultimately buying into and renaming the team before taking it from CART into the IRL.
With those varied experiences, Michael knows there are pros and cons to driving for the family operation, and says he would understand if Marco wanted to try his luck elsewhere.
"Each time was a growing experience," Michael observed. "And it also helps your spirit in yourself because then you get more confidence. That's why we like to change it up a little bit within [AGR]. I don't want him to think that he can only win with this sort of thing; I want him to know that he can be competitive with anybody he works with.
"That could be good for anybody, to go and see that the grass isn't always greener on the other side," he added. "Everyone has got their problems and there is no such thing as Utopia. So from that standpoint it would probably be good for him. It's the same with mechanics and everything. People quit and then say 'It wasn't so bad where we were at.' "
For the time being, there is little or no chance that Marco will go out and test the market. He's on the verge of signing a contract extension that will keep him in IndyCar with AGR for the next two years. At 21, there is plenty of time left for alternate IndyCar opportunities, or even F1.
"I think the U.S. is obviously where my heart lies," Marco said. "To be racing in Indy cars on my father's team and the Indy 500, that's all stuff that I live my life around. I bleed this sport, so to speak, and I don't see an opportunity presenting myself where I would want to jump all over it in F1. And that's the only way I would do it.
"I do have all the resources I need within the team, and it would just be a matter of placing the right personnel where I need it to be consistently at the top week in and week out," he added. "We want to be where every one of us doesn't make mistakes week in and week out, and we can go for a championship against guys like Scott Dixon."
John Oreovicz covers open-wheel racing for National Speed Sport News and ESPN.com.