I found this description of him online; I couldn't do better.
Ronald Colman was the personification of the gentleman hero, a type that was perhaps already 'Olde World' when Colman reigned as a star over fifty years ago. His idealism, integrity, and graciousness belong to a time that has since disappeared altogether. There is an ethereal quality about Colman that harks back to that gentler, simpler world, one we can now only visit through his films. For such a gentle man, he had a core of strength, an adherence to his own code of honor like steel - incorruptible and immovable. He could swashbuckle with the best of 'em, his comedic timing was priceless, and as a romantic star he was unsurpassed. He was saved from being too staid by a delicious wit, a twinkle in his eye that showed us he could laugh at himself and at others if need be. And always he gave us that wistfulness - it was in his eyes, in his mannerisms, and especially in that voice. That modulated, liquid voice. His way of speaking, with the hesitations, the pauses between words, somehow conveyed his vulnerability as well as his sophistication - a tantalizing combination that has not lost its power to enthrall.
Text reprinted with permission:
Ravin' Maven of Classic Film Pages http://themave.com/
Haven't you seen A Tale of Two Cities (1935)? Ronald Colman gives a touching performance as Sydney Carton, a dissolute lawyer who sacrifices his life for those he loves.
Watch this and then see these other four films.
Random Harvest (1942) Ronald Colman and Greer Garson star in this extraordinary movie.
A Double Life (1947) Here Ronald Colman plays an actor who gets a little too much into his part.
Lost Horizon (1937)
Bulldog Drummond (1929)
*Contributed by: "Katie Connolly" Date: Fri, Dec 14 2001 / 12:26:20 PST
1929 Nominated for Best Actor in a Leading Role: CONDEMNED
1929 Nominated for Best Actor in a Leading Role: BULLDOG DRUMMOND
1942 Nominated for Best Actor in a Leading Role: RANDOM HARVEST
1947 Won Best Actor in a Leading Role: A DOUBLE LIFE