Why is James Watson famous?
Watson created a model of the DNA double helix structure along with Francis Crick. Rosalind Franklin discovered the structure of DNA by using X-ray diffraction. Watson and Crick used Franklin's unpublished data without her consent in the construction of the double helix model and took credit for the findings.
If it is the character that you're referring to, his name is Dr. John H. Watson. If the computer program, I believe it was originally called a Sherlock (though I'm hardly even half sure about that, warn you). Dr. Andrew B. Watson is a NASA scientist. Dr. James D. Watson is famous in the field of DNA. Dr. John B. Watson is famous in the field of psychology.