The opener - who last played for England in August 2021 against India at Lord's - was in the runs at Old Trafford but Lancashire hit back with three late wickets at the end of the session.
The Birmingham side won the toss and decided to bat on what appeared to look a very good pitch as Sibley hit 118 from his six hours at the crease.
However, Warwickshire ended the day on 273 for seven. Sibley - bidding to return to the England fold under Ben Stokes - turned down the chance to play for England Lions before December in order to work on his game with Tony Frost - the Bears' batting coach.
The benefits of his time with Frost was on show against a Lancashire attack without James Anderson or Saqib Mahmood. Sibley scored his century from 226 balls.
His last ton was also at Old Trafford for England in 2020 when they played the West Indies in a Test match.
Burns back in business
Rory Burns also showed what he can do ahead of England's first Test against New Zealand on June 2.
The Surrey captain scored a knock of 107 as his side reached 261 for six on the opening day of their County Championship game against Northamptonshire.
Burns also managed two milestones during his innings - 11,000 runs in first-class cricket and 9,000 for Surrey. Sam Curren joined him at the crease and had a partnership of 95 for the fifth wicket.
Curren produced an impressive performance and returns tomorrow with a score of 71 not out.
Cook continues fine form
Sir Alastair Cook batted for the majority of the day and went on to score 107 against a Yorkshire side which included Joe Root.
It was the first time Root was out playing since resigning as England captain but it was his predecessor who starred.
Cook notched up 107 runs from 268 balls and put on a third-wicket stand of 174 alongside fellow left-hander Paul Walter. Essex ended the day in Chelmsford on 234 for four.
Stokes watches on
In Division Two, Stokes was named in Durham's XI but had no involvement as his side reached 339-3 at New Road.
Stokes is expected to bat at number six but watched his team-mates rack up runs against Worcestershire as opener Sean Dickson continued his excellent start to the season with a third ton.
The South African hit 14 fours and a six in his 104, and Keegan Petersen also made 50 before skipper Scott Borthwick (80 not out) and David Bedingham (69 not out) shared an unbroken fourth-wicket stand worth 117.