Third seed Halep is looking for a swift response to defeat in her first grand slam final at the French Open, and she hit just nine unforced errors on her way to a 6-2 6-2 triumph over Teliana Pereira at the grass-court tournament on Tuesday.
The Romanian has surged to world number three, and is rewarded for her victory with a second-round match with Lesia Tsurenko, who swept aside Germany's Dinah Pfizenmaier 6-3 6-0.
Williams is searching for a sixth title at the All England Club, and she started in fine fashion in a dominant 6-1 6-2 victory over Anna Tatishvili.
American Williams overcame a shaky first game where she had to fend off four break points, but that proved the only blip in an otherwise fine showing, and she now meets Chanelle Scheepers in the second round after the South African overcame Christina McHale 6-3 6-3.
Sharapova arrived in SW19 brimming with confidence after triumphing at the French Open last month, and the fifth seed once more showed her credentials by destroying home-favourite Samantha Murray 6-1 6-0.
Murray - who in 2007 was working in the Wimbledon accreditation office - was completely outclassed as the Russian fifth seed dominated on serve and hit 13 winners.
She will now look to take that form into her second-round encounter with Timea Bacsinszky, the Swiss having booked her spot via a 6-1 6-3 victory against Sharon Fichman.
There was a shock for seventh seed Jelena Jankovic, however, as the seventh seed was outclassed by 2013 quarter-finalist Kaia Kanepi, who hit 28 winners en route to a 6-3 6-2 victory.
Fellow seeds Sorana Cirstea, Roberta Vinci and Anastasia Pavlyuchenkova also fell at the first hurdle, Victoria Duval, Donna Vekic and Alison Riske accounting for their respective losses.
There was no such trouble for last year's runner-up and German 19th seed Sabine Lisicki, who coasted past Julia Glushko 6-2 6-1, and now meets Karolina Pliskova who defeated Karin Knapp 6-7 (4-7) 6-4 10-8.
Angelique Kerber was among a host of seeds who won in straight sets, with Carla Suarez Navarro, Ana Ivanovic, Klara Koukalova, Eugenie Bouchard and Andrea Petkovic all advancing.
Home favourite Heather Watson meets Kerber in the second round, the Briton joined Silvia Soler-Espinosa, Lourdes Dominguez Lino, Camila Giorgi, Zheng Jie and Madison Keys in securing straight-set wins, the latter having won her first WTA title in Eastbourne on Saturday.
Kirsten Flipkens - a semi-finalist 12 months ago - needed three sets, as did Petra Cetkovska, Alize Cornet, Irina-Camelia Begu, Belinda Bencic and Yaroslava Shvedova.
Agnieszka Radwanska, the 2012 runner-up and fourth seed, saw her match with Andreea Mitu delayed on Monday due to rain, but she resumed at 4-2 ahead on Tuesday and swiftly wrapped up a 6-2 6-1 win.
In other matches held over from Monday, Caroline Wozniacki, Michelle Larcher de Brito and Varvara Lepchenko all progressed, but 14th seed Sara Errani fell to Caroline Garcia.
Zarina Diyas was one set up in her encounter with Kristina Mladenovic before bad light interrupted play, while Vera Zvonareva was locked at one set apiece with Tara Moore, with both matches set to resume on Wednesday.