At Nebraska, he played safety, tailback (as a sophomore and junior) and quarterback (senior year), and holds a school record 18.33 yard punt return average.

[4][1] In 1960, he was selected team captain along with future NFL teammate Ron McDole, and won Nebraska’s Tom Novak Trophy.

"[6] Fischer was used for occasional kick returns in his rookie season and he recorded no defensive statistics that year.

In the September 16 game against Philadelphia, he recorded his first interception off future hall of fame quarterback Sonny Jurgensen.

[18] In the first of only four times the NFL exercised the Rozelle rule, the Cardinals received a 1969 second-round selection (35th overall–Rolf Krueger) and a 1970 third-round pick (69th overall–Colorado defensive back Eric Harris) as compensation.

In 1972, the Redskins won the NFC Championship Game of the 1972–73 NFL playoffs against the Dallas Cowboys.

Washington limited future hall of fame quarterback Roger Staubach to only 9 completions in 20 attempts for 98 passing yards, and had three sacks.

[26] Fischer and Mike Bass, the other cornerback, were particularly successful in shutting down the Cowboys wide receivers, Ron Sellers, Billy Parks, and Lance Alworth, who had four combined catches for 65 yards.

[31] Fischer's mantra "get a leg up and you own him"[32] is used today to motivate and teach smaller defensive backs how to defend taller wide receivers.

[34] Fischer's tackling technique applied to bigger running backs as well, like Jim Brown or Larry Csonka, "'Stay low, keep my head up and, when I make contact, lift and take one of his legs away from him.

'"[22] Fischer, alongside fellow Cardinal defensive back Larry Wilson were prolific defenders.

The Cardinals, in attempting to deal with the problem of having a defensive hole left by a charging Wilson in the safety blitz, found a way to try and deal with the problem in the "Bump and run coverage",[citation needed] in which Fischer would physically harass receivers.

[22][37] In the late 1980s, NFL Films named Fischer as the Redskins All-Time Neutralizer sponsored by Tums.

After retiring from the Redskins, Fischer worked as a stockbroker and owned a successful real estate business.

[22] In 2014, it was reported that Fischer was suffering from "dementia, cognitive decline, and severe memory loss"[41] and was residing in an assisted-living facility in Ashburn, Virginia.