*1930s – first reports of the use of sucrose for gel electrophoresis; moving-boundary electrophoresis (Tiselius)
*1950 – introduction of "zone electrophoresis" (Tiselius); paper electrophoresis
*1955 – introduction of starch gels, mediocre separation (Smithies)
*1959 – introduction of acrylamide gels; discontinuous electrophoresis (Ornstein and Davis); accurate control of parameters such as pore size and stability; and (Raymond and Weintraub)
*1965 – introduction of free-flow electrophoresis (Hannig) 
*1966 – first use of agar gels
*1969 – introduction of denaturing agents especially SDS separation of protein subunit (Weber and Osborn)
*1970 – Lämmli separated 28 components of T4 phage using a stacking gel and SDS
*1972 – agarose gels with ethidium bromide stain
*1975 – 2-dimensional gels (O’Farrell); isoelectric focusing, then SDS gel electrophoresis
*1977 – sequencing gels (Sanger)
*1981 – introduction of capillary electrophoresis (Jorgenson and Lukacs)
*1983 – pulsed-field gel electrophoresis enables separation of large DNA molecules (Sweeley)
*2004 – introduction of a standardized polymerization time for acrylamide gel solutions to optimize gel properties, in particular thermodynamic stability, during electrophoresis (Kastenholz)
A 1959 book on electrophoresis by Milan Bier cites references from the 1800s. However, Oliver Smithies made significant contributions. Bier states: "The method of Smithies ... is finding wide application because of its unique separatory power." Taken in context, Bier clearly implies that Smithies' method is an improvement.