First Appearance: Incredible Hulk #180 (October 1974).
Appearances: Too many others to keep track of.
Years Active: What, you expect me to know?
Wolverine's continuity has become so complicated in the years since his introduction that I'm not sure anyone knows his real history...with the exception of Ronald Byrd, who did an amazing job assembling his history into something coherent, and from whom the following is drawn (some of this is by deducation, but it coheres well enough that it should be continuity).
It was implied that in Biblical times a so-called divine warrior known as the Hand of God fought against a demonic being known as Ba'al; when Wolverine fought against Ba'al in the modern era, Ba'al believed Wolverine to be the reincarnation of Ba'al, and Wolverine had deja-vu-ish flashblacks about being the Hand of God. Wolverine was active during World War One with a Canadian military team called the Devil's Brigade. Logan had various adventures in China during the 1930s, making the acquaintance of, teaming up with, and fighting against various superhumans, including Adam Destine. Logan studied under Ogun, an immortal ninja master, in Japan in the mid-1930s.
In April 1937 Wolverine teamed with Ernest Hemingway and Puck and fought the Fascists in the Spanish Civil War. During WW2 Wolverine worked together once with Captain America (I) against the Hand and Baron Strucker; Wolverine also fought in the Canadian Army as a paratrooper. After the war Logan travelled, having various adventures and being enslaved.
During the 1950s he was active as a free agent and mercenary. During the 1960s he was a member of Team X, a multi-nation intelligence operation overseen by the CIA; the other members of Team X are superhumans and mutants, including Maverick. With Team X Logan went to Cuba, the Middle East, the Soviet Union, and Berlin. In the 1970s, after leaving Team X, he went to work for an unnamed agency of the Canadian government, working with and against various superpowered individuals including Nick Fury and Richard & Mary Parker. In the late 1970s Wolverine was given adamantium by Department H, and soon after that he was brought into Alpha Flight.
Note: For the best attempt extant at a coherent history of Wolverine's life and times, read Ronald Byrd's outstanding Unofficial Wolverine Chronology. Also see the Casey the Crime Photographer entry for a further potential link.