He ushered at 49ers home games at Kezar Stadium while he attended San Francisco Polytechnic High School across the street.
He served as graduate assistant at his alma mater for a year before being hired as head coach of Westminster College in Salt Lake City at age 25,[5] where he led the Parsons to a 3–3 record.
As a 49er assistant, Seifert defenses finished in the top ten in fewest points allowed in each of his six seasons in that capacity: fourth in 1983, first in 1984, second in 1985, third in 1986 and 1987, and eighth in 1988.
[9][10] He would soon be characterized as a coach with intense focus and superstition, whether that involved bluntness or not walking across the 49ers helmet spraypainted on the practice turf.
Bolstered by an MVP season from Joe Montana to go with a highly ranked defense, the 49ers went 14–2 (losing those two games by a combined total of five points) to clinch the #1 seed in the playoffs.
The 1992 team (where Seifert ceded a portion of the playcalling on offense to his coordinator) saw the Niners engage in history with the "No Punt Game" against the Buffalo Bills in a 34–31 loss.
It was one of only two losses for the team that year as the Niners won eight straight games to close out the regular season with the #1 seed at 14–2, as Steve Young went on to be named the league's MVP.
Seifert and the Niners had a tremendous 1994 season that saw Young win another MVP award with a historic passer rating (112.8), as the team scored a franchise record 505 points.
The 1995 and 1996 seasons saw San Francisco reach the postseason each time only to lose to the Green Bay Packers in the Divisional Round, the latter being a 35–14 rout on the road.
[12] Despite owning the best winning percentage of any NFL head coach in the league's history, 49ers management did not offer an extension on Seifert's contract.
49ers team president Carmen Policy desired to hire California head coach Steve Mariucci to the same position in the 49ers organization.
[17] Seifert presided over the 2001 NFL draft, which netted the Panthers Steve Smith and Kris Jenkins, two cornerstones of the franchise.
Seifert made the push to not retain Beuerlein as the starting quarterback, instead going with Jeff Lewis (signed in 1999) as the intended starter.
[18][17] They followed up that impressive victory by losing every game the rest of the year, finishing at 1–15 (with nine losses by eight points or less), the worst record in franchise history.
[19] The Panthers' final two games were played before what are still the two smallest crowds in franchise history (in terms of turnstile count), including a 38–6 loss to the New England Patriots that drew only 21,000 people.
[21][22] Seifert is the first head coach since the implementation of the 16-game schedule in place from 1978 to 2020 to guide a team to 15 consecutive losses following a Week 1 victory.