| 1964-1967 | Predoctoral Trainee, NIH |
| 1967-1968 | NIH Postdoctoral Appointment, Purdue University |
| 1969-1971 | Fellow, Jane Coffin Childs Memorial Fund for Medical Research |
| 1971 | Faculty Development Award, The Merck Company Foundation |
| 1975-1980 | Research Career Development Award, NIH |
| 1975-1976 | Visiting Professor, Rockefeller University, NY, NY |
| 1990-91 | Appointed Foundation Lecturer, American Society for Microbiology |
| 1990 | Appointed Halvorson Professor of Bacteriology and Molecular Biology, University of Wisconsin-Madison |
| 1994 | Elected Fellow, American Academy of Arts and Sciences |
| 1996-1998 | Board Member, American Academy of Arts & Sciences, Midwest Center |
William H. McClain was the Principal Investigator of each grant.
| 1971-1974 | N.I.H. R01 AI10257, Genetic Analysis of tRNAs Coded by Phage T4 |
| 1974-1979 | N.I.H. R01 AI10257, Genetic Analysis of tRNAs Coded by Phage T4 |
| 1979-1984 | N.I.H. R01 AI10257, Genetic Analysis of tRNAs Coded by Phage T4 |
| 1984-1987 | N.I.H. R01 AI10257, Genetic and Statistical Analysis of tRNA |
| 1988-1993 | N.I.H. R01 GM42123, Relation of Structure to Function in E. coli tRNA |
| 1993-1997 | N.I.H. R01 GM42123, Relation of Structure to Function in E. coli tRNA |
| 1997-2000 | N.I.H. R01 GM42123, Molecular Recognition of Transfer RNA |
| 2000-2007 | N.I.H. R01 GM42123, Molecular Recognition of Transfer RNA |
| 2006 | NIH records place these Grants above the 95th percentile of the distribution of (extramural) NIH grants over the last 25 years. |