Last year, he completed a small role in 'Crank: High Voltage,' and he reportedly had two completed movies under his belt ('New Terminal Hotel' and 'American Sunset') at the time of his death.
At his best, however, Haim was a fresh-faced presence, light and funny, but not without a dark edge. Here are some highlights of his career.
Haim rose to fame quickly as a teenager, debuting with a starring role opposite Teri Garr and Peter Weller in this thriller when he was 13. He's the kid brother in the family, sweet and vulnerable, until he comes to his mom's rescue with a baseball bat.
'Silver Bullet' (1985)
In this Stephen King adaptation, Haim is impish and mischievous as a paraplegic boy who believes a werewolf is behind the murders in his small town. Haim has great chemistry with Gary Busey as the crazy uncle who builds him a souped-up wheelchair.
'Murphy's Romance' (1985)
Haim has a key role as Sally Field's son, trying to adjust to life in a new town. He shows surprising maturity as a kid torn between his mom's new beau (James Garner) and his ne'er-do-well dad (Brian Kerwin).
Haim landed his first serious dramatic lead role as a misfit, lovelorn teen. He befriends an older teen (Charlie Sheen), who serves as his mentor, and he develops a crush on a girl (Kerri Green), only to see the two of them fall for each other. The film became a cult favorite and earned critical acclaim for Haim's thoughtful, sensitive performance.
'The Lost Boys' (1987)
This clever vampire horror-comedy marked Haim's big breakthrough and remains the best film of his career. As a youngster who discovers his new town is infested with teenage biker bloodsuckers (who threaten to make his big brother, Jason Patric, one of their own), Haim straddles the line between boyish cuteness and intrepid heroism while dropping sardonic one-liners throughout. He finds his ideal comic foil in the even more intense Feldman as another junior vampire hunter. The film marked the beginning of a friendship with Feldman that would last through seven more movies over the next 20 years, as well as launching both into teen heartthrob status.
'License to Drive' (1988)
Haim doesn't actually possess said license, which doesn't stop him from a night of vehicular mayhem as he tries to take out dream girl Heather Graham for a night on the town. (Feldman shows up as a scheming pal full of bad advice.) Haim and Feldman shine in this silly but fondly-remembered teen romp (a model for later films like 'Dude, Where's My Car?') as they begin to graduate towards grown-up mischief.
'Dream a Little Dream' (1989)
This time, it's Haim who plays the goofy sidekick to Feldman, who finds old soul Jason Robards inhabiting his body. The film marks the tail end of the '80s wave of body-switch comedies, and it's also the last time Haim and Feldman are sweet, likable teens. After this, their films together become grim affairs with more explicit sex and violence, like 1992's 'Blown Away.'
'The Two Coreys' (2007-08)
The transition to adult roles proved difficult for both Coreys but especially hard for Haim, who also struggled for the rest of his life with drug and alcohol abuse that began on the set of 'Lucas.' (TMZ says he was in and out of rehab as many as 15 times.) This A&E reality series showed the two longtime friends trying for a comeback together by making a straight-to-video 'Lost Boys' sequel, but the underlying drama continued to be Haim's battle with addiction. That made for riveting and sadly prophetic drama when Feldman finally staged an intervention for Haim and finally cut all ties with his longtime friend when Haim refused to get help. After the series ended, Haim did get clean again and resumed working in small roles like the one in the 'Crank' sequel, but it seems clear he couldn't stay on the wagon. We'll never know if he could have pulled off one last comeback.