Season 4 of Full House had 26 episodes and began on September 21, 1990.
The fourth season aired on ABC from September 21, 1990, through May 3, 1991. Its 26-episode order made it one of the longer seasons in the series, whose episode counts varied across its eight-year run. Season 4 continued the show’s established Friday-night period and featured the Tanner family at a major turning point.
One of the season’s defining stories was Jesse’s relationship with Rebecca Donaldson. Jesse proposed to Becky, and the couple married during the season. Becky then moved into the Tanner home’s attic, making Lori Loughlin’s character an even more permanent part of the household.
The date can be confused with season 2, which began in 1988, or season 6, which began in 1992. Season 4 also predates the show’s move to a Tuesday schedule for season 5. By this point, Full House had become a dependable ABC hit and was approaching its strongest ratings period.