The 20-year-old, who collected team and pommel horse bronze at the London 2012 Olympics last summer, scored highly with all six of his routines in Liverpool for a winning total of 90.650.
Meanwhile fellow Olympic bronze medallist Daniel Purvis claimed silver with a score of 87.250 while Matthew Firth edged out another London 2012 gymnast, Sam Oldham, to take bronze with 83.700.
And Whitlock, who won the English all-around title at the start of the month, expressed his desire to be taken seriously as a gymnast for all apparatus after stripping Purvis of the British title he’s won three years in a row.
"I'm well happy. To start the year by winning the English title, which has always been one of my main ambitions, and then to win the British is just crazy," said Whitlock.
"I'm happy with all my routines, particularly the vault which I've worked hard to improve and it's paid off.
"It's been important to me to prove to people I'm an all-around gymnast, the pommel will always be my strongest piece but I wanted to go out and show I can do all-around.
"And hopefully that will give me a chance of perhaps doing it again at the Europeans or worlds this year."
Meanwhile, in the women's all-around competition in Liverpool 15-year-old Gabby Jupp put in a confident performance to win the British title in what is her first year as a senior gymnast.
Jupp scored 56.150 for gold with Charlie Fellows taking silver with 54.900 and Niamh Rippin bronze with 53.650 and, after causing one upset, she has her sights set on some more this year.
"I'm so, so happy I didn't ever think I'd be senior British champion. The floor and vault were really good," said Jupp.
"The bars I was a bit disappointed but to end on beam, even though it wasn't perfect, suited me as it's my strongest piece.
"As a first-year senior to take the title is like a dream and as for the rest of the year hopefully I can now make the European team which would be a big step in my career."