Paul Burke was probably too old to become a major star in feature films in the wake of
Naked City
, still not forty; and then, especially,
12 O'Clock High
. He was an attractive, capable actor, though he lacked charisma, the "It factor", whatever it is that separates the capable journeyman players from the ones "touched by God" (or so it seems).
Actors of the same type (IMHO) who also failed to become superstars, or even true, competent A listers, are Cliff Robertson, who did very nicely in films, his Oscar for
Charly
notwithstanding, never made it to the top of his heap. One needn't be pretty or youthful for that. Walter Matthau got there, as did his frequent co-star and friend Jack Lemmon. Lee Marvin got to the top, gray haired and homely though he was. Then there's Clint Eastwood, a one off if ever there was one, although his career path to me rather resembles that of Sean Connery and Michael Caine, as he became, as a result of his "spaghetti westerns", an international star, then moving on to law enforcement and contemporary pictures.
On the other hand, Charlton Heston did get there, though in his case this seems due to his casting, by Cecil B.DeMille, among others, in Biblical and historical epics. I've never sensed that Heston was ever truly wildly popular, at the Gable-Cooper-Bogart-Connery level. From an historical perspective he became, with time, an icon. His moving into "disaster" pictures in the 70s showed that he really did have legs.
But Paul Burke, no. He was never going to "catch on",–unless, that is, he had some fantastic strokes of luck–and with a string of successful, serious, "socially conscious" pictures in the 60s he might have emerged as a latter day Henry Fonda, albeit lacking Fonda's larger talent. I can see Burke having a "go at it", as Franchot did in the 30s, or Dana Andrews later on. Burke lacked
gravitas
on screen, big or little. I've never seen him light up a scene due to his presence in it.

His face wasn't pretty enough for the time. During Naked City the bags under his eyes became more and more pronounced. He was a very good actor and his portrayal of Det. Adam Flint in Naked City was great. I think he wasn't a bigger star because t5b4here were too many actors of a similar type at this time and he didn't rise above the crowd. I loved Naked City and Burke's performance. Wonderful show with a great film noir theme.

Agreed - a good actor and gorgeous. Loved him in Valley of the Dolls and The Thomas Crown Affair. Don't know why he didn't become leading man material.

I don't know either. I think he was a very good actor, too. And gorgeous to boot!