125 points and 96 assist Hart Trophy winner Joe "The Rooster" Thornton is the worst player to win the Hart Trophy?
Is the op asking which player had the worst Hart season or which player has the worst career that won a Hart trophy at some point? I'm pretty sure it's #2, but I'm not sure....
In recent years it has to be Perry IMO (whether it's the 1st or 2nd option), he played on the top line in the league and had a good ~15 games that got him the trophy. I also find him over-rated... Yes he's a great player, but I never think of Perry and Hart together and I forget all the time that he won the Hart that year.
OV's last Hart win was pretty unimpressive imo, but he's had a dominant career and, again, I think the OP meant the 2nd option.
If we REALLY wanna get technically, I suppose being a player on the worst team in league while not being a particular notable otherwise would make Tom Anderson the winner. Then again, I can't judge how good he was for obvious reasons, i.e. never saw him play.
Considering Jose Theodore is mostly known for that one season, would give him the nod here amongst those I've seen. He was amazing that season, but it was that one season.
As people have said, if we're looking at career, then Theodore sticks out among recent winners. Perry as well, and Sedin somewhat too. For seasons, Perry and Ovechkin last year were two of the weaker ones, followed by Sedin and St. Louis probably. Messier in '92 a bit as well. Of course all Hart seasons are still generally great.
Going back further, Al Rollins, both in season and career is probably the worst based on history knowledge. Apparently he largely got it based on his previous season. Ted Kennedy had a great career, but his win in '55 was apparently a bit of a career achievement award (at 29!). The voters seemed to follow the idea of value to their team more before the 60s so there's a few guys who fit the bill: Tom Anderson, Buddy O'Connors. A lot of guys had short peaks then as well, so not a ton of career value for some.
Jose Theodore from a career standpoint. Guy played lights out then steadily declined. Basically a better Jim Carey.
This is my choice, and also pretty close to my reasoning as well. Theodore was the only Hart winner in recent memory who wasn't "elite" for any other seasons other than the year he won. The other Hart winners were arguably top end players for multiple years before and after winning the Hart.