The Rams and McClaren stand on the brink of ending their exile from the Barclays Premier League after brushing aside Albion to reach the Wembley showpiece later this month.
Leading 2-1 from Thursday's first leg, McClaren's men completed a 6-2 aggregate victory with a 4-1 win at the iPro Stadium.
Will Hughes' first goal since November gave Derby the half-time lead before further strikes from Chris Martin, George Thorne and Jeff Hendrick sealed the club's first return to Wembley since the 2006-07 season - when the Rams were last promoted to the top flight.
Kazenga LuaLua's late reply was a mere consolation for Brighton, who tasted defeat in the play-off semi-finals for the second successive year.
Derby will play the winner of the second semi-final between QPR and Wigan, who resume on Monday night at Loftus Road with the tie goalless.
"It will be hugely enjoyable to lead a very, very talented Derby County squad out at Wembley," said head coach McClaren.
"We wanted a performance after a rather ugly 2-1 victory at Brighton, and boy did we get one.
"We were awesome, mixing energy and entertainment to thrill our wonderful supporters.
"We looked a damned good side and were almost perfect.
"If we can produce the same level of performance at Wembley, I reckon we can be a match for anybody."
The final could complete a remarkable turnaround for both Derby and McClaren.
Upon his appointment as Nigel Clough's successor at the start of October, when the Rams were 14th in the league table, McClaren conceded there remained a "stigma" that has tarnished his career in this country, after his difficult spells in charge of the national team and Nottingham Forest, where he was briefly in charge in 2011.
He became the first English coach since the late Sir Bobby Robson to win a league title abroad after winning the Dutch Eredivisie with FC Twente in 2010 while his coaching credentials are highly regarded across Europe.
Yet McClaren has often been a target for criticism and, for many, will always carry the cruel moniker of "the wally with the brolly".
McClaren was lampooned after that disastrous 3-2 defeat against Croatia on a rain-sodden night in November 2007 at Wembley, which on May 24 could now provide the setting for his complete redemption.
He added: "I love going to Wembley. But I tell you this, I shall not be taking an umbrella whatever the weather.
"Seriously though, I should pay special thanks to chief executive Sam Rush and whoever else helped him choose me for this job.
"Hopefully, everything will come to the perfect climax on May 24."