Alan Ladd was no Marlon Brando, Spencer Tracy or Fredric March. Nor was he a Robert DeNiro, Al Pacino or Dustin Hoffman before his time. He was Alan Ladd. He was serviceable. For the most part, he got the job done and didn't ask anyone to give him an Oscar, or even a nomination, for his troubles. And no one would have anyway. It's not that he was bad because he wasn't. It's just that no one ever left an Alan Ladd movie and thought, "Wow! What a performance!" But he created characters based on his own persona that allowed for an exploration of those characters over the course of his career. Allow me to explain.
Whenever I hear someone say, "Oh (insert name of underrated actor here) just plays himself all the time" or "she's just being (insert name again) in all of her movies" I get a little annoyed. I think most people with acting experience reading this would agree that the best actors always infuse a character with their own personality, the better to establish the character as a real human being that the actor can inhabit. And more importantly, playing yourself isn't easy. When I was living at home all those years ago my mother would read through plays with me when I was memorizing lines for a part. She tried to act while doing so. She was awful (sorry Mom). She e-nun-see-ay-ted ev-vuh-ree word in some bizarre Stratford-on-Avon mock British construct. It was unnerving. She was under the false impression so many have, that anyone can act if they're just playing themselves. They can't. Reading lines and making them sound like words that you just happen to be saying doesn't come naturally to a lot of people. Alan Ladd may not be Edwin Booth but he was good at his craft and knew his limitations. Like his frequent co-star Veronica Lake, he never attempted to go outside of his established low-key persona. And as I said in the opening paragraph, that allowed him to develop one character over the course of his career.
Alad Ladd became a star with his portrayal of cold and calculating Philip Raven, the hired assassin of This Gun for Hire in 1942. Eleven years later he had his biggest success with Shane and every time I see either of those movies I think of the other. To me, Shane the character is Philip Raven, older and worn down. I don't mean literally since they obviously take place in different times and Raven dies at the end of his outing but inside the psyche where the character resides. Shane is Raven, older. I can imagine Shane spending his earlier days shooting people for money and as much is implied in the film. Shane understands Jack Wilson (Jack Palance) because Shane was Jack Wilson when he was Philip Raven but now he's fighting the good fight and doing it free of charge. And the only reason I can get that character lineage from Raven to Shane is because Alan Ladd played himself in both.
When an actor creates a wholly new character for each performance, like a Marlon Brando, Paul Muni or Meryl Streep, you can't follow a character over the course of their career. But when they play themselves, you can. Take John Wayne, who excelled at placing his personality at the center of the character he was playing. Doing that makes it easy to imagine that Ethan Edwards of The Searchers is the older version of the Ringo Kid from Stagecoach. The Ringo Kid has none of the bitterness or rage of Ethan but he's young and inexperienced. Because of John Wayne's persona I can easily see him becoming Ethan over the long haul and it allows me, when watching The Searchers, to "remember" what Ethan was like when he was younger.
Another great example, this time over the course of three movies, is Paul Le Mat's characters from American Graffiti, Handle With Care and Melvin and Howard. That's the same guy at three different stages in his life. Can't you see the hot rod drag racer of American Graffiti becoming the trucker later in life before settling down to an empty, low-income existence in the Las Vegas desert? Those three movies are a way of seeing what the Graffiti character of John Milner would have become had he lived on.
Sometimes I imagine the character fell into a downward spiral somewhere along the way. Think 
about the Elizabeth Taylor of A Place in the Sun or Father of the Bride becoming the raging drunk of Who's Afraid of Virginia Woolf. Or what if Vivien Leigh's Scarlett O'Hara finally snaps under the pressure of constantly having to fight for everything and becomes the hollowed-out shell that is Blanche DuBois in A Streetcar Named Desire? James Bond of Goldfinger is given up by the agency as a scapegoat and the CIA locks him away for decades until he's the silver-haired incarcerated secret agent of The Rock. Joan Crawford's musical star of the stage in Dancing Lady becomes the wheelchair-bound has-been dependent upon her sister in Whatever Happened to Baby Jane?
It's fun to imagine these character connections but also surprisingly useful in fleshing out a character beyond what the film provides (in fact, I couldn't even have made it through The Rock if I hadn't actively imagined that was James Bond after 35 years of imprisonment). Shane doesn't overtly provide background details for the title character though it is implied throughout. Fortunately, Alan Ladd made it possible to see what Shane was like before the 1953 movie came along by playing the character in an earlier incarnation in This Gun for Hire. And that was possible because Alan Ladd played himself, which may make him appear limited to some but it also made it possible for him to do what Paul Muni never could: Create a character and spend the rest of his career building a history for him.
