Not quite. McKinley was elected to two consecutive terms, but was assassinated in the first year of his second term.
Also, Calvin Coolidge probably could have breezed to a second election victory, but politely decided to "choose not to run.
OH, sorry, yeah, each time I’ve posted that I’ve also noted “and completed both terms” or just said, “served two terms in his own right”. :’(
Coolidge is a woulda shoulda coulda, fact is, he didn’t run, and as it turned out, would not have quite finished a second (third) term.